well, if it's somewhere like a supermarket or the average public place, i don't use it unless i'm about to crap my pants and then i hover.
the only place i use the seat with confidence is at work because we have a bathroom just for our staff, so maybe like 5-8 people ever really use it and it's always really clean so i guess i feel safe.
i'm going to schedule any AIDS test for when i get back from my trip.