I read a bunch of years ago in Branded by Alissa Quart of American schools where soda giants would fund equipment for the sports teams and provide free soda for the cafeteria. So the school would both have to pay for their own drinks in the cafeteria and refuse sponsorship of the sports team to avoid being involved with soda the companies. It just makes economic sense in that case to let the soda company rope the kids in.
It's been a while since I read it, and I can't verify the truth. For me, it sounds like schools should have no part in getting kids addicted to soda.