JSquared2 said: "If a block of tickets was given to, say, the ad agency, they probably wouldn't know who was using them --- but at least they knowto tell the ad agency one of their people was caught selling comps. Then the ad agency will deal with it internally."
In that scenario, the ad agency may use tickets in any number of ways. They may give some to a delivery boy as a tip. The delivery boy may then give them to his Grandma because she likes theatre. She may not want to go so she sells them on stubhub. No one is going to scold or hold the ad agency responsible.
In any event, once a show gives comps to an agency, or anyone, in trade or to grease wheels or whatever, they have no say over what that agency does with them. That's like buying a coffee and telling Starbucks they can only use your $3.50 for rent, but not supplies.
Art has a double face, of expression and illusion.