Yes agree, affiliates should recognise they have a very good deal if they do have no negative roll over set up with a program and not think its only right that they should.
And an even better deal if a program seperates that negative roll over by product..
ie. I send a sportsbook player who wins a large amount in sports, he then (feeling a bit rich) plays a bit of casino and loses leaving a negative rev share in casino that month, some programs would clear the casino negative and pay the sportsbook rather than rolling the commissions together.
Not exactly fair eh?
But on the flip side any good affiliate I think can justify asking for no negative roll over on the basis that if a player/ or players do win then surely the program will want the affiliate to keep sending volume players through rather than stop and wait for the negative to even out or give up altogether and promote another program instead.