The problem is that the hotel cancels the entire stay as a no-show at some point in time, apparently in the middle of the night. Or even if *that* doesn't happen, if the hotel sells out, this is the easy guest to "walk"...meaning when he shows up at 8AM, there's no room.

Threads on several of the hotel boards about exactly this scenario. People willing to pay to show up in the middle of the night or early morning, and then it not working out well at the hotel. One guy even got double-charged for doing it: charged for the no-show, and then charged for a new reservation checking in at 3AM or whatever. (An error that was eventually worked out, but still...)

Starwood's 24-hour clock for its super-plats is the closest thing I've seen to a solution for this. (At least among the mainline brands that most of us have access to. )