If the minor commits a crime with the item, it's not on the community, it's on the vendor that sold it to him.
If you as a minor come onto a forum asking where you can get say... the finest in wine in a box available, and someone on that forum tells you go to the LCBO or whatever spirituous beverage vendor that is nearest to you, and you dupe the cashier into selling you the party in a box, it's not on the forum, it's on the vendor who you duped for not checking/verifying you were of legal age to purchase such refreshment.
However, being as it is, the airsoft community is fairly small, and it could be a slight oversight/momentary sleight of diligence that the gun was sold to a person not of verified age. In which case, you can let the admins deal with that if this guy is indeed the AVer for the region.
Also, to play devil's advocate, there is no magic barrier that is broken or magical enlightenment that occurs the second you turn 18. So let's not jump the shark thinking this guy will run around the local park brandishing his newly ill gotten sport shooter. What's done is done, and while lying about being 18 to get a gun speaks about one's honor in a sport of honor, alienating the guy now could cause the very problem you seek to avoid.
Of course, if he had any integrity, he would return it to the vendor.
Last edited by lurkingknight; June 5th, 2012 at 14:36..