Originally Posted by
MSPeconomist
Could the extra reservation have been made around the time you called Marriott (or the hotel) for some reason? There are reports of call center agents (not sure I've seen this for Marriott) forgetting to close an account when they go on to the next call.
I do all of my booking online through Concur at work, but I'm sure something like that could still happen. I'll see what I can find out tonight and update in case this ever happens to someone else.