I have. Riding around town/easy riding is fine; I was just too lazy to strap in/out. Did it brakeless as well for a year.

I did crank it really hard from a stop (with good chain tension and lube), and the chain popped,
dropped my left foot to the floor (flintstones stop), my balls on the top bar (no padding =/, but i was saved), and my right shin ground up.

pics for reference.




switched to my straps on my scraper bike (not nines) which have been giving me less knee problems as well as a much better crank rotation.