Yea!!!!!!
Karen, the POINT of the TRAP is to TRAP the predator. Use any means necessary. Really unlikely they are going to see the trap and think "gee, guess I'm supposed to walk in there so the door can close and I'll be unable to get out". Have to give them a REASON to walk into the TRAP.
We have actually trapped quite a lot of raccoons and a couple of skunks in un-baited traps. I don't think we have ever caught a possum in an un-baited trap though.
7 eggs for me today.