I have personally sat on the bottom of the Puget Sound and watched a square crab trap fish. The crabes will indeed go around the pot to find the opening. It appeared to me that the crabes could have cared less. They just wanted the goodies in the pot.

I did notice that all the crabes will show up on the down current side of the pot first. Probably from smelling the bait.

If anything, I'd make sure the trap door to the pot sits on the down current side. You'll definitely get more crabes in the pot that way.

And no, I did not tamper with, or "raid" that pot. I just sat off in the distance and watched it fish. I already had my limit of crabies. Scuba diving for crabes is the only way!