You know, you guys sometimes have this amazing ability to carry on an argument under a set of very constrained circumstances.
Here is my experience:
In MOST cases, there is no reason for a player to play extremely tight to a bunker AND not switch positions except to hide a hit. There are exceptions, and refs need to be aware of when a guy is just in a very tight position, but if a guy slides into the snake and may have a hit on him, just freaking pull the guy off the bunker for a second to check him. There is plenty of room back there (in most cases) to move the guy AND not have him get hit.
And if that means he can't shoot for a second, well, that's just tough ****. Getting checked is part of the game - if you took heat on the way into the snake, or you see the ref coming at you wanting to check your inside, make your life easier and SHOW THE REF WHAT HE WANTS TO SEE! If you're not wanting to do that, and you're going to force the ref to unnecessarily go in there to FORCE you to show him, the only person at fault for the consequences is you.
In my experience, the players who make it really hard for you to check them are the players who really don't want to be checked because they think they are hit. And even if they are not ACTUALLY hit, I can't have a whole lot of sympathy for negative consequences to the player caused by the player's own behavior. Hell, using Nick's example - if I see that you're playing as if the most important thing to you is keeping one side of your mask against the bunker, you can bet I know what you're doing and I'm going to come and ask you to switch sides so I can see what you're hiding, and when you pretend you can't hear me, I'm going to pull you away from your bunker to check you (usually, I'll stand in front of you so if anyone is going to be shot it'll be me and push a gap between the area I want to look at and the bunker) and not care if you still get shot because I know that you think you're already shot and your unwillingness to follow directions and make the check easy is the problem.