I haven't had this come up yet, but would it be possible for an investigator to pick up the locked suitcase or the unsolved puzzle box and take it to another party member?

I can't think of any reason why they should be able to do this even though it isn't necessarily within the rules.

You can't pick up obstacle cards. You pick up cards when you explore, and obstacle cards prevent you from exploring.

I guess I was just thinking it was a bit (and I hesitate to use this term considering the content of the game) unrealistic, and was hoping for something other than the rules don't allow it (because I know that they don't) as to why they shouldn't be allowed to. It's not like moving the puzzle gives them any advantage to solving it (except with the possibility of moving it out of a dark room.). They would still need to solve to puzzle to get inside. But then again this may never actually come up as an issue in play but it had been bugging me so I thought I'd ask.

If the investigators wanted to pick up the locked suitcase, I would allow it. I don't think it would help them too much though... because I'd force it to be an action to pick it up...and why not just use the action to solve the puzzle.

The only other thing I'd be concerned about would be setting a precedent for picking up obstacles. I'd just make it clear that it's only because this obstacle is applied to the suitcase.

just my 2cents

I'd suggest just explaining it, if you really need to, like the suitcase is attached/locked to something in the room, or is otherwise immovable. Honestly, it's just a random description to make the lock name different, mechanically it does not function any different from the other obstacles in the game. As fun as it is to pretend this is a RPG, it is actually a boardgame, so some things are abstracted. It would be like saying Harvey has a cane, so he comes with a melee weapon, or why can't an investigator break a chair leg off to use as a melee weapon, or why can't the investigators barricade doors (other than with barriers), or a player has a torch and wants to make a second torch out of a dowel and rags from the closet, etc.

It's a boardgame, not an RPG, so a lot of things aren't freeform or flexible and just cannot be done.