I don't understand what Renault have done wrong here, they didn't deliberately not bother doing up the wheel nut to save time in the pitstop and Alonso slowed to a sensible pace so that when the wheel did come off it didn't fly miles and he kept control of the car. Trying to get back to the pits is just common sense.
The three recent high profile incidents involving single seaters and debris are not as related as people will try to make out, Massa had a truely freak accident, probably the only non-pitstop component to fail and fly out of the back of an F1 car for years and by complete chance it happened to hit him.
Alonso's wheel flying off was a result of a poor pitstop, quite a few wheels fly off cars due to not being fitted correctly during pitstops, normally flying off at much lower speeds and causing less harm than wheels/debris flying about for other reasons.
Poor Henry Surtees was not killed by a freak accident, it was an accident waiting to happen. Everytime cars have a big shunt debris poses a potential risk (and there are far more wheels flying off cars from driver error than pitcrew error), the chance of debris ending up at head height above the track is pretty low, the chance of it hitting a driver is tiny. Cars are crashing more and more now with drivers thinking they're safe, when John Surtees was racing the chance of getting hit by a stray wheel would have been much lower because people simply crashed less, had the guy who went off been racing on a tree lined circuit he wouldn't have been over confident and had an unforced accident in the first place from pushing too hard. The increase in debris and accidents resulting from other cars having avoidable accidents is getting worrying, my mate who races in F4 has had two crashes involving stray wheels coming across the track, one which ripped a corner off his car at Brands Hatch and one which glanced his head at Snetterton (literally leaving tyre marks on his helmet!), both caused by silly car to car contact and neither freak accidents by any stretch of the imagination.