I was just reading BrightlyBob's posting that the LHR Renaissance cheats him of points on a consistent basis.
I have had problems with this with Marriott Hotels, as well.
When I had a simply horrendous experience and asked for compensation as bonus points to my Platinum Marriott Rewards account, the manager at a Marriott balked. It was an argument. Why would they make a big deal about rewarding me with a couple of thousand points when they could lose me as a customer?
Does an individual hotel in the Marriott chain have to pay for the points they give out?