If you are in good-enough standing you can pioneer on 0 hours a month. Although it was not spelt out to me, I told the CO that I could not continue pioneering because I could no longer do the hours or anything like. However the CO did not want me to step down. Whatever I could do was acceptable. For me that was 0 hours. But I imagine I would have been expected to lie or have a plausible excuse every month/year. However no one would have questioned me.
But what happens to your conscience when you lie about something this stupid? You don't have to do it so why do it unless the status is important to you.
I think they main things was that they could get me on the platform and use me as an example. But I wasn't going to mislead others so I stood down.
Also I know of elders and their wives who would REGULARLY have it announced that they were pioneering get the applaus, then they would just not do it and say they had been ill.