In NZ it is most definitely seen as a commercial operation by CAA.
I know this because after raising 10's of thousands over the years for charities they told me to stop. Their way of thinking is that because the punter is paying for a flight, it is therefore hire and reward!
They wrote a vector article about it some time ago, their suggestion was that if you wanted to donate to charity, "then you should bake a cake" (greater risk from my baking than my flying!)
In fact I was told by the General Manager GA, that I should go ahead and do one of these flights so that they could test the rule in court!
My reply cannot be repeated here.......Muppet's.