Fuel fines are most definitely not a tax. It's just a way airlines have to raise prices without being transparent about it. The reason why US/CO and other US-based airlines don't charge their frequent flyers YQ for award tickets is, I believe, that in the US fuel fines have to be built into the the fares, so they can't be charged separately. That said, I'm not sure if VS does charge YQ for award travel on CO or US. I certainly hope not.