When I first started acquiring games, I didn't have a proper dolly or even straps yet. I would borrow a tank dolly from work when I needed to move a game. There was a Centipede that had been on craigslist for over a month that I talked the seller down to a reasonable price on. I was doing an exterior water proofing on my basement at the time so around the entire front perimeter was a 6' deep 3' wide trench. To get in my front door I had a 2x10 board that extended over the trench, one end on my front door ledge, the other on a set of half demolished concrete steps. To get a game in we'd put it on the tank dolly, unstrapped, pull it up 4 concrete steps then a few feet over an unanchored 10x2 board with about a quarter inch clearance on either side of the wheel base and the board ends.
I had already moved a couple of games in without incident so even though the set up was hairy, it worked.
I was almost done bringing in a Centipede with a friend when one of the dolly wheels started to scoot off the board. I felt it happening so pulled back quickly on the dolly to get it through the door. The wheel fell off putting the wheel shaft on the board. When I pulled on the dolly, instead of pulling the game, I pushed the 2x10 board forward. The end of the board fell off the front door ledge, as the game started to follow, my friend jumped back and I let go of the dolly so I wouldn't follow a Centipede into the hole.
The game gods smiled on me this day. The game fell backward so that the top half was in the door entrance and hit the door ledge at about the half way point of its height. Because it wasn't strapped on the dolly and the dolly back was rounded, it twisted to the side at the same time when it hit. The game wedged itself in the doorway rather than tumbling into the trench after the board end.
I now had a Centipede wedged at an angle half in my house and the other half hanging over open space with a tank dolly trapped underneath it as well.
My friend climbed in the hole and pushed up on the bottom of the cab while I pushed down on the top of the cab. We first had to wrestle with it to get it off the dolly and the dolly untrapped and out of the way so we could get it on it's back in my house. Then we just pushed it in and set it upright again.
Worked fine and my buddy stopped answering my calls whenever he knew I was doing a game pick up.