A rogue trader's warrant outlines what his power, and his duties to the imperium are. It also elevates him from whatever social position he was in and puts him on the same platforms as planetary governors, high ranking tech priests, some inquisitors, and maybe space marine captains. Sector (and sub sector) lords, chapter masters, Cardinals (or higher?), high ranking inquisitors, and some planetary governors as well as the heads of forge worlds would all likely be on a slightly higher social level than the Rogue Trader.

Also once in the Imperium it's somewhat expected he'll follow most imperial laws dealing with the ruinous powers, xenos, and non approved technology. It's also expected that he'll treat his social 'superiors' with proper deference.

In effect he has to stop being Han Solo and instead become Princess Leia.

If he doesn't then at the least his reputation will take a hit, which can affect his business interests. At worst he'll draw the ire of some very powerful people who have more influence in their area than he does.

That's one reason people like WInterscale, and Chorda don't really leave the Koronus Expanse all that often. They may be the biggests boats in the bathtub there, but once through the maw there're people who are just as important, and some of them may have questions about where they've been.

To some extent, this discussion made me think about Qadaffi son's behavior in Europe a few years back.

He used his diplomatic immunities to behave like a total jerk in France, Switzerland and Danemark.

He wasn't arrested due to his status but they were some serious diplomatic consequences

@renoh: nicely put

One point I think I should make since Arbites are being tossed around a lot in examples. There is a difference between Adeptus Arbites and planetary enforcers. Adeptus Arbites uphold the Emperors law and the Enforcers or whatever they are called locally are the regullar police and are the ones you are most likely to encounter unless you've all been very naughty boys and girls. The Arbites are usually (I know of a few exceptions) meant to be housed in a fortress court house that in different descriptions have been described as able to survive orbital bombardment or seige for years. Basically if the planetary governor falls to darkness and/or the world with him/her then the arbites hold out and try to re establish order and kill the corrupt governor (I imagine they'll probably have one hell of an inquiry after this by senior arbites and probably the Inquisition).

Inside the Imperium if nothing else the Rogue Trader is an extremely rich and powerful noble. They want to carry around heavy weapons and such I'm sure they can get a special dispensation from the planetary governor after much bribing or promises of trade etc which should keep the enforcers off their backs. The Arbites probably will keep an eye on this but as long as the Rogue Traders don't go breaking the Emperors law then it's not their job, if they use said heavy weapon to blow up a rhino of arbites or attack an Imperial Guard recruitment centre or try to launch some kind of anti imperial campaign thats when the big boys come out to play. They've got storm trooper carapace, combat shotguns with special rounds, shock mauls, cyber mastiffs and rhino's whereas I've seen enforcers detailed using light flak coats, stub automatics and clubs...

It really depends on the world, if the hive world is landunder the locals aren't going to let anyone come on with a heavy weapon as it's not very structurally sound and normally people are never allowed any form of gun... lots of knives though! I could see maybe with a lot of smoozing a rogue trader being allowed to have an unloaded bolt pistol but that would be tough with this world. On Scintilla the sector capital of the Calixis sector it might be a good idea for the rogue traders to play nice since Lord Sector Marius Hax is a very paranoid man who has the power to grant warrants of trade, he's also very protective of his sector and anyone messing around right on his doorstep might be something he'd have to act on unless it becomes common for rogue traders. Warrants have been rescended in drastic cases before and Hax might have an outside chance of doing this if he needed but heavy weapons are not in that category. Still its not good to draw his attention unnecessarily. I was in a game where the Rogue Trader destroyed his enemies the Fane of Tokara in some bloody sudden political and military manouvering... he got an invitation to meet Hax and for the first time ever the Rogue Trader was scared, Hax pointed out he must have made a lot of enemies with his actions and gained the notice of others and told him to get out of the Calixis sector for the next twenty years.

While a heavy weapon is probably going too far, the Rogue Trader book explicidly says that no Rogue Trader would ever be caught without some kind of weapon, be it an ornate pistol or Digi-Laser hidden in a ring. It doesn't make dispensation for specific social situations.

My personal take would be to invoke the rule of cool...

Profit Factor isn't just about how much money you have, it's also about how much influence. But it also gives a fair indication of how much PASSIVE influence the Dynasty can wield. The more outrageous you act and dress, the more power people think you have (we're talking 40k rules here - where sublety gets you shot). So, a pair of examples:

Example 1: A group of individuals are walking down the main road of Mercutia Secundus. They're wearing a mix of heavy carapace and power armour and are loaded for bear. Many of them are carrying Boltguns and Pistols, and one of them is even carrying a Multimelta.

Expected Arbite reaction: "Get some teams over there. DO NOT PROVOKE THEM! Find out from the local mercenary companies if they have dealings in the area."

Example 2: A group of individuals is walking down the main road of Mercutia Secundus. THey are preceeded by a number of gold leaf painted slaves who are strewing cherry blossom petals in their wake. Surrounding the group are a number of bodyguards, each with a ceremonial las-lance and clad in burnished copper carapace and stylised helmets looking like various savage beasts and monsters from legend. In the center of the body guards float several individuals in fine clothing mounted upon a grave-barque pulled by a team of cyber-destriers, each protected with the vague shimmer of a Refractor field. They seem oddly amused at the 'quaint' hive structure around them, even as their fan-servitors ensure that the fumes from the air around them are tastefully diffused by the cunningly concealed incense burners built into the long, peacock feathered fans. Behind the group walk a number of servitors, each a sculpted golden beauty, bearing the groups personal quipment. Boltguns and bolt pistols are in evidence, each wreathed in smoke from the servitors sacred machine incense burners. The grandest of all the servitors bears in its hands a multi-melta, inscribed with platinum and covered in purity seals. The servitor, in a surprisingly sprightly female voice, quietly lists out a number of names in an endlessly repeating pattern. Those listening can realise that it is a list of the vehicles this weapon has destroyed in the seven hundred years since it was constructed.

Expected arbite reaction: "Wait... what? They're dressed in... Okay this is above our pay grade. Get some teams down there to keep the beggars back and see if you can politely find out where they're headed. ****, I didn't need this this morning. Where's my caffiene, dammit?!"

If a Multimelta is brought to a planets surface by people who are clearly looking to use it? The arbites will look poorly upon it. If a Multimelta is brought along, seemingly as set dressing? They're going to panic that you're rich enough to cause way too many problems if you're detailed.

I am overwhelmed by so much decadent baroque grimdark coolness

I wish my players had such imagination ^^;

Some food for though there professor_kylana seriously cool scenario in your second example, where the RT has even more guns around them but giving the distinct impression they're not here to start firefights.