This morning at 8am I was exiting the Luxor garage, and five cars were in front of me. There was no attendant in place. It became immediately obvious, that the exiting process was going slower than it should, as it took about a minute per car to exit.
When I checked in, the front desk gave me a green plastic card with the hotel name on it, to use to exit the lot, while I was staying. The desk made it clear it was usable at any MGM property on the Strip.
Once I got to the exit machine, it wasn't obvious where to put the card (the size of a normal credit card), and the wording on the unit was non-informative. I slipped it in the most obvious slot and it went about half way, and nothing happened. Removed it and didn't see any other obvious entry point, so I put it back in the original slot. After about 10 seconds, the machine sucked the card in. A few seconds later the card came out and the gate opened.
This ain't going to be pretty, during prime time for ingress and egress!