Just tried it on a flash cart. I can pickup items, but they are not removed from the world since $FFF1 is > $5000.

Edit: I could implement a check for $FFF1, if requested.

Edit 2: I suppose you could say this code also prevents thieves.

When I get some time, I'll fix up the code and port it to 1.1 and EU (if it's not already working).