At our hotel, we'll get people who arrive at the airport late at night, say 11:30pm, and then they come straight to our hotel and try to check in, saying "I have a reservation for today." Well, yes, you have a reservation for a room for later this evening and check in time will start at 2pm this afternoon. They'll try to argue that they reserved a room for Wednesday, and now that it's after midnight, that makes it Wednesday and we should have a room for them. Essentially, they want a room for late Tuesday/early Wednesday for free, when they only booked a room for Wednesday evening. The poor night auditor has had to put up with several guests trying to pull that trick this year. If we happen to have an empty room when they arrive, we can sometimes give it to them at half the normal rate, but sometimes we are sold out, so when they stand in the lobby at 1:00am demanding their room, there is nothing we can do for them until 2pm.
In a nutshell- booking a hotel room for one night means that you get the room from 2pm (check in time) until 11am the next day (check out time). You get use of the room for 21 hours. These people want to get use of the room for well over 24 hours, at no extra cost.
My family and I recently visited a resort known for its family friendliness and indoor waterpark. It is always booked solid. It took us months of planning to get a reservation during the peak season. When we arrived, I went to the front desk to check in and the lady in the next line was arguing with the clerk that she didn't really need a reservation that EVERYBODY knew that hotels keep empty blocks of rooms "just in case" and that EVERYBODY knew that those rooms were cheaper than the rest because the hotels were desperate to fill them. (These seem like contradictory statements, but I blame Priceline commercials because she was using almost the exact same language.)
When the clerk explained that he was sorry, the resort was full, she pitched a fit, pointing to her three kids (all under 12 and standing there loaded down with pool rafts and vacation debris, looking very embarrassed) and yelling that she'd PROMISED her kids a vacation at this resort and that they drove eight hours from their home state to get here. So... she planned enough in advance to drive eight hours to a specific resort, but didn't think to check the availability on the off-chance she'd get a discounted room?
She immediately demanded a premium room at 25 percent of what she would have paid for a regular room and she wanted to upgrade to a host of resort fun packages for FREE just to make up for her trouble. I finished my check in and walked away from the melee before I found out what the result was, but the expression on the clerk's face read, "Uh, no."