In many FPSes one can crouch to improve accuracy, in TF2 it’s not clear if crouching improves accuracy.
Does crouching improve accuracy for any of the classes?
What about a spy’s pistol?
What about a heavy’s chaingun?
How about shotguns?
There’s an article on the wiki about crouching, and it says no, regardless what weapon you use:
Crouching does not increase your accuracy when firing a weapon, unlike in other Source games.
When you see Spies or Scouts crouching while firing their pistols, either they aren’t aware of this (i.e., as Dave says, they do it out of habit), or they crouch to avoid being seen, good for hiding behind barrels, low walls, fences, etc.