I'm curious as to how Marriott defines "checked in" at their properties. Are you officially checked in once you've done so on the mobile app, or are you not "officially" checked in until you're physically standing in the lobby? I'm a Platinum Elite, and after I've checked in on the mobile app, I'll often call the hotel to inquire about available upgrades. Sometimes I'll get them on the spot after they've verified my reservation, and sometimes I'm told upgrades are subject to availability "at the time of check in." When I point out that I've already checked in on the mobile app, I'm told I'll have to wait either until the day of check in, or until I'm physically at the hotel. In my opinion, checked in is checked in, whether you've done it via the mobile app or at the front desk...but perhaps that's not correct?