For what it's worth, way back when the AV systems was there, the retailers would actually call you up. I mostly dealt with Ranger's airsoft, who called me on every sale.
The obvious solution is to deal within the classifieds, but I realise that's not the most profitable move. I know other local forums have a form of AV sometimes, some retailers accept this as par to ASC's AV system.
Don't kid yourself however, a sworn statement is worthless and (with respect) a bit naive.
The whole advertising issue on ASC opened up a can of worm, where do you think the kiddies go to when we tell them the classifieds are out of their reach?
At the end of the day though it's your business, your money, your call. Not that I have something against you personnally, but I'll vote with my dollars and buy from AV retailers.
Maybe you guys (retailers) should network and compare notes on how you screen for minors.