Children & helmets

In the USA many states have helmet laws for children. Superficially this seems a pretty reasonable argument. Children often fall off their bike as they learn to ride and do stupid stunts that only a child could think worth pursuing. Children also don’t go very fast or interact with heavy traffic (as a general rule) because their riding is more playful than purposeful. So they seem ideal candidates for protection from ground impacts. In fact one study I looked at attributed a quite high number of children saved to the dual actions of mandatory helmet laws and parents who think cycling is dangerous (in regions without the MHLs to force their hand).
Unfortunately the same study concluded that a slightly greater number of children died as a direct result of wearing their helmet on the playground. I know many parents who work very hard to indoctrinate their offspring to wearing their helmet every time they get on a bike. It is difficult to explain to a young child that they must wear the helmet when riding, but they must never wear the helmet when they are playing off the bike. Yet every week children are strangled by the helmet strap when they get the device caught in playground equipment.
So making children wear helmets saves perhaps 19 from death by head injury for every 20 it kills by strangulation on the playground. Is that a winning scenario for anyone? At least it has a potential solution – better education and perhaps youth helmets need a breakaway strap?
This issue doesn’t even touch on wearing the helmet properly, which seems hard enough for many adults (nevermind the kids). The front of the helmet must point forwards. The straps need to be snug and done up tightly. The helmet must sit level on the head and it must fit correctly (not too large so the child can grow into it, nor too small because they recently outgrew it).