I took a promotion without a pay rise on the agreement it would come when pay was reviewed annually. A shit deal, but one I was prepared to accept on the balance of things. I made clear that if they didn't follow through then I would immediately demote myself and start looking for a new job.
Pay review came around and it was below inflation. I immediately demoted myself and started looking for a new job. I even requested an internal transfer that was denied (made them too much money where I was).
I handed in my notice a short while later and everyone was, to my surprise, surprised. I really didn't understand why the shock....until I learned in due course that most people don't follow through.
Funnier still, I returned 6 months later (due to a quirk in contracts) at double the salary in the dept I requested a transfer to.
Anyway my point is - do what is to your benefit, always. Companies can play games - as can you.