The last pedal I had "come loose" the whole pedal slid right off the spindle, never had a pedal actually fall out of a crank. I keep a 15 in the portable tool box due to the number of cheap or track bikes I give quick tunes to. my standard 15 also doesn't fit a lot of pedals, there's a reason for the thickness of the average pedal wrench. But the one I do keep in the repair box is also one of the best ratcheting combination wrenches you can buy, one of the few sizes I think is worth investing good money on since its also the most used sizes for hard work.