Questions about kink3d fitting events

I am considering going to a kink3d chastity fitting event near me. Has anyone here been to one of these? If so, how do they work? Do you get more expert fitting advice than if you buy online? Are you obligated to buy once fitted?

(I had a k3d device but I was never sure about fit as my method was to stick with the first one I could wear for some time, even if it may not have been optimal.)