taking photos at public sporting event

I am a individual photographer, trying to get my business going. I live in Ohio. I recently went to a baseball tournament, all the players are under 18. I took photos at one game because a particular team asked me to come and photograph thier boys, while I was there I also photographed the other team. I then passed out business cards to the other team that did not know me. The field is a public field and anyone is welcome, there was no fee to get in. The are no signs posted about taking pictures. I was asked not to give out my cards because another much larger company said the had a contract with the association putting the tournament on. I posted my photos on my web page and I received an email from them asking me to remove them saying they had an exclusive contract with the association and that if I did not I would be billed to cover their lost sales and game fees. These tournaments last about 6 days with approximately 24 games a day. I have been told that at a public sporting event anyone can take pictures and sell them if they are not being sold for commercial use and I have also been told that if you are taking pictures of anyone under age you must have a release signed. Did I have to legally not offer my photos for sale and can they bill me if I did? What is the law for this kind of business?

[Law200]

You can shoot photos of pubilc events unless the forum has rules that you must agree to before you enter. You cannot use team pictures etc. for sale normally unless the team approves. It can get to be a grey area in some situations.

Ask to see their contract as a first step.