Anytime I need to plug in and go to bed (due to a long day or some other reason), I will leave my contact information in my window along with permission to unplug my car if a charge is desperately needed. It's slightly annoying to receive a text in the middle of the night informing me that someone unplugged my car, but I'd rather deal with that than have prevented a latecomer from charging because I was hogging the station.
That's a good idea. I tend to come in really late myself, and I've yet to be in a situation where the charge completed before morning. Some hotels only have 30A, and I've had to unplug without the charge finishing.