We actually called the hotel specifically and called to double check and got a different answer and called again and got a third answer. (11:59pm day before check-in, 11:59pm second day before and 4pm day before). In the end the first answer prevailed after a fourth call. Ridiculous though. SPG had it right and it varied by hotel as well.

Surely Marriott can still give the hotels the right to set their own cancellation policy and time, yet at the very least record that time in the system somewhere, even if members can’t see it, so customer service can. Oh hang on, that might be asking a bit much of their IT.