We've hired many times, and have met all sorts of reactions from all sorts of boaters.
We've shared locks with private boats, and ended up having excellent chats with the crew, who often know that stretch of canal very well and have all sorts of tips to offer. On the other hand, there have been private boaters who assumed we didn't know what we were doing and whose arrogance preceded them; and the ones who'd just had their boat painted, and were obsessed by not scratching it (in which case I wondered why they'd gone anywhere near the Lapworth flight, with its narrow locks, tricky short pounds, and fierce by-washes).
We've also come up against the sort of hirers who must have been the ones who gave hirers a bad name in the first place: who despite having a crew of six send only one to operate the lock; who apparently hadn't been told that they wouldn't get very far if they opened the paddles at both ends; or who didn't think it necessary to leave the paddles and gates closed when they'd gone through.
As far as helping other crews, I usually wander up with my windlass, make a friendly offer to help, and try to get a conversation going. If they want a hand, it helps everyone through quickly; if they don't, I'm happy to stand and watch.
In general, though, it's fairly easy to see who has a clue and who doesn't. If some boaters choose not to see and prefer to carry on with a superior attitude, I think it's generally them who are missing out.