I've gone through quite a few bikes and have had zero issues with QR levers. I've even had axles break on mountain bikes and had QR skewers hold long enough for me to get home on several occasions.

Now that most of bikes I ride have disc brakes, I'd rather have through axles just because it's a little easier to align things right, but it's not like I'm worried about safety. TBH if someone really can't pay enough attention to make sure their QR is set up right they probably shouldn't be riding around to begin with.