Pottering up the Llangollen arm past a line of moored boats a few years ago I spotted a hire boat ahead and the 'father' of the group, on seeing us approaching, obviously hurried up his 'crew' to unmoor and proceeded to pull out ahead of us. No problem I thought, we're in no rush so he will get away from us. Oh no, quite the opposite, he then proceeded to swan along barely above tickover, slowing down for every narrow and bridge hole and, despite my hopeful, gentle approaching behind, made no move to let us past or even look behind him, even when he came to an almost complete stop in a bridge and our bow nearly overran his stern! We had to follow him all the way to Llangollen taking twice as long as hoped, at which point he winded and headed straight off back towards Trevor!
We weren't in that much of a hurry but he did make it very difficult to keep control of the boat as I was having to drop into neutral regularly as we couldn't go as slowly as him in tickover.
Having said that I have had equal problems with Private boaters and generally find the issue is not whether they are hire or private boats, it's the people on them that are the problem!