Here's the problem with you getting mad at the Run-DMC T-shirts going out of stock: how do you know who actually bought them?
You leaped to the conclusion that the 14 year olds went and bought them all (also leaping to the conclusion that each and every hypothetical 14 year old customer who is running around with the shirt is a genuine phoney). How do you know it wasn't all 20-somethings or 30-somethings who bought it?
Coming from someone who got too mad at 14 yr olds while at a corporate mega-store and being misguided enough to share it on a message board susceptible to anonymous pricks tearing you up a year and a half ago... just chill, yo.