And thus we should also eliminate every other prescription because any minor can pay an adult to buy it. After all, no one can prove that I'm actually using my Vicodin. Maybe I'm selling it. (sarcasm complete)
Um, no, he or she can only pay an adult who actually has a prescription in the first place, because those are the only adults who can legally buy those drugs.
That's not the case here, is it?
I don't think there are currently any drugs which require prescriptions only for minors.
Use some sense, people.