I've only ever had one clipless moment, but I've never used clipless, and my foot wasn't on the pedal at the time. I stopped, and then dithered momentarily about whether I was putting my foot on the kerb or in the gutter, so it landed half and half, then slipped off into the gutter, and over I went. The natural reflex to move my foot left and catch the fall was thwarted by the kerb.
I felt the urge to give clipless a try once, but never found any suitable shoes that fitted properly, so I've cycled in 'ordinary' shoes all my life, but never had any problem with them. I've only ever owned two* pairs of toeclips in my life, a chrome pair that went rusty back in the 1970s, and the pair of Christophe plastic ones that I bought to replace them. Can't say the same for the pedals, the only thing I've replaced more often than those is the tyres.
* I do actually have another pair that came with my Horizon, but they look like they're designed to fit wellie boots, so I've never used them.