Our Class A is older than most, and may be older than many reading this. I keep the air system tight enough that, if I secure it at shut down, it will still pressure at restart. It does not have jacks or slides and so I can't even relate to those issues.
There some things here that do matter.
As an owner and driver of diesels for over 50 years, I can assure you that idling them won't cause them to "warm up".
As an engine professional for many years, I can tell you straight up that nothing good happens in an idling engine. Fact is, that used to be a durability concern. That has dropped by the wayside as the first Arab Oil embargo convinced many to drop the habit.
Lastly, a lot of what is the complaint here is not just here. It is a dramatic drop in both consideration of others and acceptance of personal responsibility. I am not going to go into examples because said are just too numerous to even start that here and now. It is even a lot of the reason that we try to avoid commercial destination campgrounds.
Matt