That's funny about the Joker roots! Glad to hear it might be adventitious, kinda makes sense now. The prices dropped pretty dramatically for that one over the last few years, ease of propagation might just be why.
I think Circus Circus might be, too. I had mine in a spot where wild roses were taking over so I moved it several years ago. I had a few plants pop up in that spot a few years later, one of which I left in place long enough to bloom. Sure enough, Circus Circus. I don't think I left enough of the original root to have had eyes but since I was fighting off wild roses to get to it I might've.