I am not sure how the situation transpired that evening or whether the strippers are actual employees of the establishments (actually it should not matter) but the bar, club, etc., certainly has an obligation to announce that certain behavior regarding touching the dancers is allowed or prohibited. It should also provide personnel to enforce that announcement. There is not much that the dancers can do once they start providing the entertainment. However, the dancers should understand that none of those actions will be allowed with or without consent (so no extra moolah).