I would avoid it if they want to take a cut of your cookies as a referral fee. The margins on decorated cookies are slim enough as they are. If they love your work, they should be happy to refer people to you regardless, without skimming off the top. I used to design all the wedding cakes for the Ritz-Carlton in St. Louis (their internal party planner referred everything my way), and never paid them a cut of anything - they got my full price. Not all customers chose to book with me (that is of course always at their discretion), which is another reason to avoid referral fees. Also, be careful with whom you align yourself, as their reputation may reflect on yours.