i photographed a whole little league - girls's softball, t-ball as well as harball for an entire summer. i think there were something like 80 teams in the league. i never experienced any sort of kickback scheme.
... but i did have a weird experinece with a guy who was the manager of a camera store that wanted my business. since i got a better deal at another place ( custom cropping &C for free! rather than a fee) he got his team to boycott my photos.