Chappo's right, nowhere does it say you can't use it for maintenance rides. In fact, on all my 'pink tickets' is the condition (which is the same pre- or post-log book system) "G094 "Use only in conjunction with an authorised club event or maintenance".
You might not want to test out the full 50k's radius from home as used by one club I know (most clubs are 10) but there is nowhere anywhere that says maintenance rides are out if you're on the log book. The logbook system is simply an addition under "Special Conditions". I'd like to see the written basis for being able to be nicked for it, especially if you're clearly doing something like fuelling up or doing a bit of test riding in the vicinity of your registered address. The copper who "let you off" probably knew that too.
I believe there was resistance to the logbook system by some people in some car/bike clubs. I can only imagine they were paranoid types and thought nobody would turn up to club events anymore if they were free to ride anywhere they pleased. Nothing could be further from the truth. Club memberships are booming, there are more and more people on club runs AND there are also some who simply pay membership to use the concessional rego and in doing so, improve the financial position of the club to put on better and better events for those who do turn up. Any opposition to the system should surely have been filtered out by now? It's totally illogical.
And even if your club does have a rule which somehow over-rides the G094 condition (which I doubt is legal), it's not the bloody masons or the cammora, you can just join a club that doesn't. There are plenty.