Food rules

My library, like many public libraries, is a city department, and one of the things that means in this case is that we have to follow a lot of health/safety-related rules in our programs. One of them is that we can only serve pre-packaged food at library programs. That's usually not an issue since we never have money to buy food, so normally we don't serve food at all. However, we have a craft program that is run by a volunteer, who loves to buy food with her own money and bring it in. It's very nice of her, but I am constantly in a battle with her about following the pre-packaged rule and other food ordinances. To be honest I'd probably let it go in other circumstances, but she and the people who attend her program always leave a huge food mess behind, so this is part of my strategy in trying to make bringing food so inconvenient that she will stop and then my staff and I won't have to clean up after the program anymore.

Last week I was wiping down the tables in the program room where her craft program takes place and saw that someone had put a banana in the trash can.  My coworker was in there setting up for the next event and so I rolled my eyes and said "[Coworker], the craft volunteer brought in bananas this week!" Without looking up from what she was doing, my coworker just shrugged and said "Would you say a banana is 'pre-packaged,' at least?"