I don't know about you guys but I always look before sitting. In a public restroom I always wipe the seat or line it w/ TP.
I wonder what kind of cleaning chemicals would do this. That's some high powered stuff if this is true.
A woman in my restaurant asked me once why I leave the seat up. She said she nearly fell in.
I said that I leave the seat up so that no one pees on the seat. I told her that if she doesn't look to see if the seat is up or down, she'd never see if there was pee on it.