Great suggestion, but it just doesn't jive with reality. People are going to play casually and adapt to their local standard of play. I don't think most people go in thinking "I'm want to break the rules today and I'd better ask permission". They develop habits based upon play with their friends and local groups that they aren't giving thought to and are likely perceived amongst those groups as within the framework of the rules. They most often aren't even going to initially be thinking "I'm taking a shortcut here, I should ask permission" This is why it is sportsmanlike to give a warning (or two) if someone goes to do something out of order, but allow it initially. They likely aren't even cognizant of the issue.
The fact that you have to give players a warning or two in order for them to play by the rules is a little bit of a goofy concept when you think about it isn't it. But I understand it can become habit. So can just playing the rules out right in correctly, and I don't think anyone would allow someone to re-roll a re-roll for instance. But I've seen worse from certain playgroups that just don't know the rules of the game.
In my mind, not being understanding of these situations and taking a hard line on rules obeyance is bad for the community - even if things are on the line in a tournament. I hate to imagine a person who learned to play amongst friends taking the plunge into their first tournament and then having their opponent forbid them actions as described. That will be a lost player for the game for sure.
And if there issues are just plain not knowing the rules of the game? Where do you draw the line? Do you just let that player do pretty much whatever they want in fear of offending them?
You know what I think is worse. A player taking the plunge into his first event, expecting to play a game by the book, only to get taken advantage of by an opponent that plays fast loose with the rules; because that's how it's done at that store.
The rules are there for every player to learn.
There's no reason to abuse an opponents ignorance of the rules, but not following them should not be the default for a playgroup. That type of play only leads to problematic situations.