Interestingly enough we ran into a similar situation while in Nashville this summer. Couple came in late, like 9:30 pm and let their DP idle for 20 min. It wasn't so much the noise as the fumes that bother me, so yes, I was slightly annoyed but so be it. The next morning they were leaving at around 8:00 am and the wife of the couple came over and warned me that they would be warming up their rig to leave. I thought that was a nice gesture, ironically they actually just fired up and left. I am quite mechanical and know a lot about diesels and the need to let them cool down, however if it were mine I would have either let it cool down in a parking lot next to the CG or out by the check-in being that it was that late in the evening. Ultimately it wasn't a big deal, just had to close our windows on that side due to the exhaust. Definitely only a tiny blip on our vacation, didn't let it ruin a good time.
EDIT: I will add that the male owner of the DP mentioned to me in the am that "this place is pricey". So, I believe he was annoyed at the price just for them to stay the night while passing through.At that point he probably didn't care about disturbing anyone. LOL
