Haven't fallen. Shimano M520 with spd cleats. FWIW, I never fell back in the day with toe clips/straps either.

I have a theory that people who "lean" to the side when they stop are way more likely to fall because they didn't unclip than those of us who don't lean but come off the seat in a forward motion and keep the bike basically upright while stopped. I've even had people argue with me that it's impossible to stop with one foot down without leaning. I don't even want to get into what they are doing wrong (do we have to shoot some video footage?). But I think a lot of the fallers are leaners because they usually start their falling story with "I unclipped my right foot but leaned to the left and fell that way," or some such thing.