I can't comment on what it's like in New Zealand but what you have fallen victim to is the hangar gossip syndrome that is rampant in Australia.
Some schools do require PPLs to sign the MR each flight, unless a CPL has already signed for the day. Why? God knows. Students learn this and don't realise it's a company not CASA requirement, move on and and teach people this rule as fact. No one bothers to check because as you said the rules are a mess, you can check 3 volumes (AIP, CAO, CAR) + advisory publications and the things that are worded plainly are usually contradicted somewhere else.
I sound like Jaba!
