In fairness to Choice, it is published in the Choice Privileges guidelines that rates that are discounted above a certain percentage (25%, I think) are NOT eligilble for promotions such as the most recent "Stay 2 times get a $50 gift card".
On the other hand I have seen dirty dealing on both sides, for example Choice using phony pretenses to strip a property of its branding, and some Choice properties staffed or managed by people who have no business working in the hospitality industry. Also, some employees treated very badly by ownership/management. But I don't doubt some of this goes on in other chains as well.
In the few years I've been a CP member I've learned what properties to stay at and which to avoid and how to get maximum benefit from CP promotions, so it's worth it for me to stay with the program... for now.