Nr Fairy,
nobody is saying here that wearing a helmet will save your life in case of an accident, but it should be obvious that it will increase your chance of survival.
Hopefully one day the manufacturers will get their heads out of their...and install airbags in every machine.
Any good car you buy these days has at least 4 to 6 airbags up front (front, a-pillar and side airbag on each side) there is absolutely no reason they couldn't be installed in every machine.
Nick, if you're reading this, you think we might expect this in the near future (keeping your recent question in mind on what could be improved.)?