Unless this girl is the most unsanitary person ever, she did not get herpes from the toilet seat. She most likely had sex or had a guy go down on her and she just doesnt want to admit it. Too bad.
Anyway, the only way you can get herpes from a toilet seat is if someone rubs their herpes infested privates on the seat and you IMMEDIATELY expose an open wound or another opening to that exact spot.
I dont know a single girl that has not mastered the art of hovering. So, she is pretty much an idiot.
HPV is another story, but pretty much everyones got at least one strain of that, and no it does not mean you have warts.