I can't really speak from a boys point of view on this topic but as a girl personally I would just wait till I got home. There's just something not comfortable about doing your business in a "foreign" toilet surrounded by strangers. Sure I'll use one in public if I ABSOLUTELY have to but otherwise I'll just hold it till I get home.
I spoke to a few people earlier today on this topic and most were either with me or just didn't care. When you gotta go, you gotta go!