I really don't care what others are wearing, to be honest. If they come in drunk and obnoxious, that's another story. Saying that, I've seen men in tuxes who were quite drunk and obnoxious.
I'm also not really sure if going in shoeless is a health hazard to anyone but the person who is shoeless. I have never yet heard of any bacteria that can jump from the floor to a tabletop. I have heard of people getting infected with bacteria or fungus from contacting them with their bare feet.