Ed Bilodeau has a few words about food/drink/trash policies. If you feel that you must have them, enforce them.
I am calling on librarians everywhere to pull yourself away from the Internet and take a few minutes every day at different times of the day to take a stroll around your library and ensure that your policies regarding food, drink, and general proper use of the library are being respected.
When it comes to policies, there is a strong tendency to “have our cake and eat it too”. We don’t want to enforce policies (and of course the great majority of the time we don’t need to), but we sure want them in place those times we do need to confront a patron about their behavior. That isn’t the way policies actually work, of course – see how far you’ll get in a court of law if you have not been enforcing a policy consistently, and applying it equally to everyone.
We don’t have policies. We have “guidelines.”