Register the copyright for your work product at www.copyright.gov. You can complete the form on your own and it only costs about $40. If you register the work within 3 months of creation and/or before they steal it, you can seek statutory damages and attorney fees. That's a hammer.
The alternative is getting paid before you present the work.
Good luck,
Todd
Answered on Sep 12th, 2014 at 2:33 PM