...what appears to be under discussion are the ethics of selling out of a room when other vendors are paying to be there.

I've worked ren faires where we had nothing but rain all weekend. Patrons didn't show up, no one made any money, but the vendors ensured that the faire would last by supporting it with their booth fees.

Pehaps, given the demand for dealers who do body make-up, massage, henna, hair extensions, the Dragoncon powers that be might consider a separate "services" area?