Let them undercut. Promoters and club owners are going to realize that fucking with those snakes is fucking with their money. For example there is this club her in Cleveland. Used to rock Thursday through Saturday with no problem. The dj was dope, I want to say he was making around 300, 400 a night. Then he was undercut by his boy (at what price, I have no idea). The club lost momentum after that and now the owner is to the point where he is willing to get anyone in there for any price, as long as things get back to the way they were.
To undercut someone in any business is bullshit, but cats will wizen up sooner or later.