If your not doing your job to the best of your ability, then while you might be "sticking it" to the company IMHO your just cheating yourselve and you co-workers. I can understand you being upset with your contract, but regardless of how it happened it was voted on by YOUR membership.Properly executed it is not stealing time...
Stealing is stealing whether they stole some of your benefits by lying about what might happen or if just giving a half effort and expecting full pay.