Generally, we leave our plates for the Room Steward to remove. But, on one cruise, (I'm sorry I can't remember which one
), Room Service asked us to call them when we were done so they could remove the trays and we did that.
I wouldn't leave a tray in the hallway. It's hard enough to walk or "scoot" through there. There
are exceptions (i.e., Mrs. Tennille). In your case I'd call Room Service, tell them I'd left trays with plates in the hallway, and depend upon them to do their thing
!