Permaculture Graduates and subsequent PDCs

I want to get some feedback from the Permie community about the cost of folks who have a PDC certification, attending a 2nd, 3rd, 4th etc PDC.

I thought that permaculture etiquette allowed for folks who have already take a PDC to attend subsequent ones for free. This discounting of course the costs of housing/food if the even is being catered or if housing is being provided for those attending.

What say you permies? especially interested in hearing from PDC facilitators.

I've heard of that practice in the context of becoming a permaculture teacher, but then I believe you are expected to help out with the course in some way. My assumption would be that you'd have to negotiate this with individual course organizers though. To your point in the initial question, someone would need to cover the cost of food, lodging and instructor fees.