Based on mere accusation, they can do this. In fact, based on your description of the situation, it sounds like a situation that happened to someone within my circle of friends earlier this year. It's nasty crap that can be pulled on anybody at any time.
Of course, I know another situation where a guy was pissing behind a tree in the woods during a party, and a 14-year old neighbor girl who dropped by for the party went around to chell him out. As a result, he went to jail for exposure with amorous intent, or something equally ridiculous. Problem was, someone else saw him, too. Nobody respects privacy anymore....
However, without material proof (signs of violation, the girl's testimony, or a baby), I doubt they can do much more than hold you pending trial, which is bad enough. Whatever costs you incur, you may want to go ahead and tell your lawyer to sue the fuck out of Mommy Dearest for her loose lips...mental distress, lost wages, compromised reputation, your butt-raping in the holding cell, etc. Also (bearing in mind that I don't know much about how the courts in your area work), you might try to petition the court for relief in lawyer fees and court costs, so if they dismiss the case, then Mommy Dearest has to pay it all herself. If that happens, I hope your council generally bills his hours by 15-20 minute increments. She'll be ass-raped by the legal system if that's the case.
Failing that, withdraw every dime you have in the bank and put out a hit on her.
