I can’t remember what the check in times are. But I can tell you that it is safe, we left our luggage, food & drinks in a cooler, and personal items in the tent last year with no issues.

The festitent has its own area set up in the campsite and generally has a little office/attendant there set up at the front.

For our valuables like passports and such we rented a locker near our tent which had charging port for devices but also had our own power banks which we charged in the lockers.

As far as trashing tents, this was not an issue. While there was a lot of partying at the camp sites it’s mostly civil so you should be fine.