If you do the occasional sprint, you might consider some float. I have used systems with no float, and personally experienced 'release' while in the middle of sprints. Thankfully I've only come away with some serious welts and a few glancing blows to the 'equipment'.
I know of one rider (experienced one for sure) who 'pre-released' during one of the numerous sprints on the local Sunday Hammerfest. He ended up being carted away.
Next time he was seen on the bike he was sportin 'toe straps' around the shoe and pedal spindle ... sortta like old-fashioned ski 'safety straps', except as insurance in case of any future pre-release.
All it takes is just a quick jerk in the wrong direction to easily overcome 'no-float' systems. And in a sprint your legs/feet can do some crazy things. Even a strong pull of not quite great technique, say while climbing out of the saddle can have you flailing air.
Course you can also overcome float systems as well, but it usually takes much further movement to click out.
Couple of weeks back I was out on one of my older machines, sportin a 'no-float' system. A City bus rolled by and I decided, last minute to catch on back for some dirny training. Thankfully the inadvertant release happened only 5 strokes into the 'sprint', so I wasn;t really up to full steam - But I raked the calf pretty well with the pedal anyway. Bleed like a stuck sow for the rest of the ride home.
Float may feel a bit 'sloppy', but really, if you're 'in' then you're in and all the power goes to the pedal. But when you're out ... stuff happens...