Instruction for hirers is never going to be particularly ffective. Imagine you've just driven countless miles, unpacked everything from the car, looked wondrously at the boat and can't wait to get away. Then some bored old fart presents you with a checklist and inventory, stresses the penalty for damage, and particularly about not clogging up the toilet, and finally you get away. In this instance you've had the benefit of lovely sunny weather and probably a couple of tinctures and you have expected someone else to have done their job.
It's not just hirers who are so inattentive. I recall waiting behind a boat and butty at Aynho Weir lock , Captain Cargo, who used to play at working boaters complete with bowlers and neckerchieves and spent a lot of time telling anecdotes to passers by. The motor was above the lock, with the butty in it. After 15 mins I tied up and went to investigate and lend a hand to the 3 already on what I knew was a heavy gate. As I passed the bottom gate, the paddle was still raised, so I pointed it out to them. The response from one of them was "oh, who'd ever be a boatman?" 'not you at that rate' I replied. The stony stare was still there at Nell bridge.