I'll answer your last question, first.. Being careful about leaving the girls, or a boy, alone with a woman, has been good info in the past, however, today that isn't any less threatening, but it's a fair start. However my niece is still undergoing withdrawals from learning that a gym teacher has been abusing her daughters' friends for 2 years.
Regarding your concern about what to do to protect your kids and keep them safe.. I treat the gay problem much the same way I teach them the most basic and obvious everyday threats. I teach the kids not to touch a hot stove, look both ways before crossing the street, don't eat anything given to you from strangers, and never ever trust a queer!!
BTW, I tell them to stay away from anyone that gives them a queezy, creepy, or just plain bad feeling..so that covers most liberals as well.. :-)