I've thought about this before. So, if memory serves me correct, it is in Ben Falks book The Resilient Farm and Homestead
he briefly mentions this subject. He often hosts small groups on his homestead to teach, and those that smoke or are taking pharmaceuticals he asks to use the toilet, and those who don't take any pills or smoke may pee on the compost pile. It's been a few years since I read his book, but that is what I remember.