Dommes who have a lot of rules like to start giving them before the session. If they have a website they spell it out there. If you contact them via Email they spell the rules out there. Yeah they occasionally add one or two at the beginning of the session.

Rules can serve multiple purposes. You are obsessed with the misconception that for a large minority of Dommes their primary motivator is sadism. That is flat out wrong. For 99% of them it is making money. In second place for most is domination. You conflate dominance with sadism. There is indeed some overlap between dominance and sadism but they are by no means identical. Most Dommes are much more motivated by dominance than sadism. Imposing rules are a way to express dominance.