I was in Austin for a wedding and had reserved the house for the bride and her parents the night before the wedding.
Unfortunately, the festivities ran a bit long the night we were supposed to check in. We got there relatively late in the evening, and the AC was off, and the temp was over 90 inside. So we decided to stay elsewhere for the night.
Overall good communication with the host, and he mentioned guest needs to turn it on.
One thing I would suggest is as the host, you should be clear and upfront about the AC needing to be turned on by the guest when checking in, or ask the guest when they are checking in so the ac can be programmed to turn on accordingly.