At my University it was well known. I did not partake, however.
I have never heard of public bathrooms being cited as places where people with normal "orientation" hook up. OTOH, homosexuals have defended anonymous restroom sex going back to before the age of AIDS. Even after it is discovered, the more radical Gay-stapo soldiers have even condemned monitoring of restrooms in colleges and, in one memorable case, a Sears store in Northern California (Link not for the squeamish; not even close to work-safe).
In pre-AIDS San Francisco (mid-70s), there were residents of an area surrounding a small park who complained to city officials and police about gay men meeting in the bushes along walkways for sex at all hours of the day. Among the defenders of the practice was gay activist Carole Migden, a lesbian.
Migden is now a State Senator for San Francisco.