You can't control parents, and you certainly can't control stupid people who may or may not be their friends.
My guess is that in almost all of these senior shoots, the parents are the ones paying, and they are the ones buying the larger prints and packages. I would also guess they aren't buying a 20x30 because it is a "senior portrait", they are buying your images because it is a shot of their child that is unlike anything else they have.
Agreed. Thankfully they sent me a private message (not on here) instead of asking publicly. I just never want someone else to think something like that and me to end up on MSN.com with millions of views because I took a bare shoulders image of an underage girl with none of her top showing. Though, perhaps all press is good press.