They won't deliver to an unoccupied room simply because they hope to be tipped. These CMs pretty much live off those tips. When using DME, tips are already included, so they will deliver to an empty room.
Ah, but you borrowed a cart from Luggage Assistance! Not the same as Bell Services. The deluxe resorts have Bell Services...everyone else has Luggage Assistance. With LA, you will get your bags but it can take quite awhile....especially at the value resorts. They wait until they have a sizable amount of luggage to take out, and then go. They don't get a call from a guest and immediately go get the bags and deliver them. With BS, you get almost immediate service. I have never waited longer than 15 mins for my bags to get to me.
At the deluxe and DVC resorts? I doubt that Bell Services is going to let you use their luggage carts. I have never, ever seen a guest with one..unless they were accompanying the CM who was bringing the bags to the room.
I have used one at Pop...but I had to leave my license with them, as well as my room number so they could access my account if needed. I took the cart, loaded it up (had an Owners Locker that was very heavy) and took it to the counter to have it checked and the OL taken back. Then, they gave my license back.