I believe how you use the room is not Marriotts concern.
In order to get Bonvoy credit, you just need to check in "personally" .... need clarification if olci can be considered as personally check in .... and pays for the room.
The term "stays" pretty much shows that you dont have to actually sleep in the room.

Mattress runners ... who "personally" pays and check in to a room (and leave the room unused pretty much didnt breaach the t&c)