My dad and stepmom are going on their first of many trips to Vegas this year. They are concert goers. They will not be gambling at all, maybe $100 in a three night stay. Can I book them rooms through the MLIFE website and get the tier credits? The stays I would book for them will be paid stays using "gold tier discount" and just add my dads name to the hotel stay. Or should I just book the retail price through the hotel site and add my MLIFE number then?