Funny thing, just last weekend, 46x17 was behind me when:

1 - my right foot came unclipped while skipping down a hill. Didn't hurt the beans, and I was able to make a turn onto the upcoming street without much issue. (first time it's come unclipped in like 6 months)
2 - Going through a light a guy in a jeep decided to turn right while I was right next to him. Had to cut waaaaay fast and thought I was going to lose it, but didn't.

The key to riding clipless is to always make sure your pedals are tight. Besides unclipping, the only downside to clipless is that trackstanding isn't as easy, since you're worried that if you lose it you won't be able to clip out in time. I'll take the greatly increased power transfer, even if I can't trackstand and occasionally come unclipped.