The only group we have 'ever' banned from 'ever' setting foot in our hostel again, were a group of baptists.
They caused so much damage to our hostel, because they had no respect for anyone or anything but themselves, it took 20 hours of solid cleaning, to get the hostel back into a condition that we could again have guests stay in. They cost us 1000s in damages that they refused to pay for until we had to take them to court. They only stayed for 3 days, I thank my lucky stars it wasn't a week.
Then after all of this, they rang again the following year to book the hostel again, can ya guess what they got told to do with their booking????