Oh, if they are giving him points or credit plus that rate, it is almost definitely for a timeshare presentation. There is no other reason for them to do this. It sounded to me like he was using points + cash. I'm not aware of any legal maximum, just that the material almost always says how long the presentation will be, and you don't need to stay any longer than that. If you walk out before the time is up, they can revert your stay to full rack rate. Sheraton/Vistana is not know for high pressure though, so getting through it is not really a hassle.