We just returned from a 19-day vacation - all Marriott - w/5 paid and 14 Reward nights. At every check-in, we asked for an upgrade when one was not offered. Of the 5 paid nights, we were upgraded at the 3 full service hotels (2 Marriotts and 1 Renaissance) without asking (1 suite) and treated exceptionally well (because we disclosed our anniversary in these 3 reservations). The other 2 paid nights were at the Fairfield where we had to ask for an upgrade - 1ce awarded and 1ce not. Of the 14 Reward nights (5 stays), we were pre-upgraded for 7 of the nights (2 stays) - to a 2-bedroom Penthouse suite at Residence (2 nights) and for 5 nights (1 stay) where we declined their lower floor upgrade offer. We were not upgraded after asking for the remaining 7 Reward nights (3 stays). C
I have noticed the same issue. I travel a lot for work and sometimes I'm disappointed that I didn't get an upgrade but sometimes I don't care. If I'm on vacation then I always ask for an upgraded room usually just before I check in. Sadly, too often the front desk doesn't even thank me for being a Platinum member instead they just ask "points or a market item?"