I got a region A (American) copy of Shoot 'Em Up which is region locked (which i did'nt know about at the time).
After i put it into my UK PS3 and clicked onto the filmes icon (BDMV), the machine thought about it and a message came up in big letters saying REGION INCOMBATIBILITY. Then it goes back to the PS3 menues
Tried it a few times and it done the same over and over again.
So on the last try when the "region incombatibility" message came up i pressed the triangle on the controller, which brings up the pop-up menu and clicked on "TOP MENU" then BINGO the films menu came on .
Everything on the film works OK and the film plays all the way through.
I dont know if this would work on other titles?. But it works on this one
Other reported region A(region locked) titles that also work are (Which are all from New Line):
Hairspray
Mr woodcock
Rush Hour 3