This is off-topic, but I presume you are not talking about Europe? The only aerodromes at or above 7000ft in Europe are classed as altiports and a mountain (or site) qualification is a requirement, not merely a recommendation.
You are right, I am talking about the USA, where no such "mountain rating" is required. However one would be a fool to fly into a 7000' airport without doing some training, but essentially everyone who flies in the USA is exposed to high alt airports...
But stats can be used to "prove" or disprove whatever you want. I bet you could prove that IR'd pilots have a higher fatality rate in IMC conditions than an IMC rated pilot for example. I base this on the fact that more IR'd pilots have been killed in CFIT type accidents than IMCr'd pilots. IN fact saying this, you could prove (via stats) that the IMCr'd pilot is in fact the most safe pilot - less have been killed in CFIT accidents than IR'd pilots, and less have been killed in weather related accidents than vanilla PPL's...Therfore there must be a safety case for the IMCr?