I don't have any experience with quilting guilds, but I've seen a lot of discussion on the topic for knitting guilds, which are similar.
In my opinion, if a guild member is a professional teacher and gives a class comparable to what you would get at a show, (and how much would you pay for that?) they should absolutely be compensated at their professional rate. They may discount, due to it being their home guild, but this is their job. If it's a member sharing a quicker technique, then a token payment is okay.
My husband is a teacher (for the military) and he spends 30 hours a week outside of the classroom working on lesson plans in order to make the material easier and more relatable for all of his students. I'd be willing to bet that any good teacher spends a significant amount of time preparing (and updating skills!) outside of the classroom, which is usually discounted or ignored.