Generally each property must pay for the points they issue to their guests, that rate can vary depending upon their arrangement. Whether they are sitting in an account waiting to be issued or just paid for as they post is unknown. My guess is the reason some properties opt-out is due to the extra work they need to do for new promos and the such. Process changes, marketing collateral, and staff to process can be hefty. If they feel it won't bring them much in the way of new revenue, I can understand them wanting to walk. This does make it tough on the guest having to remember to ask if they participate (and hoping you get an accurate answer) and then having to chase the points if they don't post.