As an early teen back in the 80's I was out and about the neighbourhood on bikes with a mate. For some reason we had swapped bikes and as we rode along I popped a wheelie as I hopped off the kerb to cross the road in front of an approaching car. While in mid hop the front wheel fell out and I obviously had a less than graceful landing but luckily wasn't badly hurt. No idea why the wheel of his bike was loose (nuts, not QR) but could have done with the safety tabs.
A couple of months ago I fixed a puncture on the front of my sons bike. When we were out later I could hear the front brakes rubbing as he pedalled. Upon investigating I found I had omitted to fully tighten the nuts and they were only a firm finger tight. Thanks to the safety tabs there was no chance of the wheel dropping out in a hurry, giving us the chance to notice and correct the mistake.
I have been frustrated by the apparent inconvenience these tabs cause in the past but actually, with further thought and experience I can see the benefits massively outweigh the negatives!