I have never noticed any cat in a cattery hissing at its neighbours. I think they are all in such a state of shock that they don't respond as they might at home. Mind, most catteries mine have stayed at have complete separation between pens, so not really a reliable indicator ...
The only cat I have been responsible for who responded badly to a cattery was Ralph who refused to come out of his travel box for the entire stay, and only relaxed when they faced it to the wall. He was very relieved when I arrived to take him home, lol