Thats a hoot cinives!
I recently had my daughter bring in a boy who wanted her to go to some fast-food hang-out. I said, "well, let me talk to the boy, and we'll see how it goes."
So he comes inside, is very polite and engages me in 35 minutes of small talk. He is a straight A student. Goes to such-and-such church. Helps little old ladies across the street. His dad is a nuerosugeon (not kidding) and he was so well spoken!
After well over half an hour I said "nah, she's not going anywhere with you today." Man was my girl ticked off. Took me an hour to get her calmed down and see my point of view (she was only 15 at the time).
LOL - and she thought it was a slam-dunk. Tell her about the fallacy of false credentials.
I have a daughter who just turned 15. My approach (since Dad is not around and I don't seem able to scare any guy) is to make sure she spends so much time with her horse and working at the barn (women run it) that she doesn't have the energy to even think about boys. Not to mention that hauling 50lb bales of hay and controlling 1100 lb horses make her less than a pushover. It also helps that we homeschool and I'm very well acquainted with the families of her friends. :)
I will warn you that this approach is a bit expensive, however.