Lawyers make good money out of this sort of thing. At Le Mans I always ask the chap in front to sign a "model release form", as if I ever were to make money out of all those pictures of the back of his head, he'll want a share.
There must be easier ways of making money. All that downloading, sorting, burning etc for a few quid. Unless you sell thousands of course.
The other problem is that photos on the web are not high definition - perhaps only 400 pixels wide, which is OK on the computer screen, but when printed as an A4 callender, your frogeyes gets blurred