Yeah, that kind-of sucks. I've seen my fair share of quirky con games over the years, some GMs seem to see them as a way of testing out their latest wacky narrative or mechanical concept before they try introducing it in their home game, or put some unique twist on a well-trodden story.
Which can be fine if you know it's coming, but if you're just signing up to a random game on a board in hopes of getting a taster of a new system, or finally getting to play a favourite one that nobody in your local group is interested in, you really want to just be able to experience that game properly.