Replying to Rules of the urinals

I feel like there's some gray area here.
Obviously I'm not going to reach over and give the guy next to me a handy, but what's the rule on taking a peek? Don't you ever just want to compare?

Am I small? Am I more wrinkly than average? There's really no way of finding this stuff out other than taking a look.

I usually angle myself towards someone if they are next to me to let them know that it is ok to take a look if they wish.


So, what urinal rules do you have, or wish there were?