Havant covered this for quite a while but I used to supply local papers and tourism with pic's. Ive just been asked by a stock library if I wanted to supply them with images, some of which are surfers who I dont have any model release from. In the past Ive got-ton model release which has been a pain in the rear, firstly I got permission from a young guy 16 yrs old, then his parents wanted money, then the surfboard manufacturer wanted money. The shot was only for tourism who were willing to pay $50. Such events as rodeo's and riders etc used to be ok to use the images but things seem to of changed now everyone talks legal action if you get your camera out.
I still shoot a little for local tourism and use only my family in the shots, anyone else doing events etc, as Im slowly getting back into photography.