The only way for providers to sometimes get around this is to give the prescription in hand and say DO NOT use this unless your condition progresses beyond x days. I doubt all the patients listen to this, but some probably do. There are too many who come in with viral illnesses (laryngitis, common cold, flu, ear infections, acute bronchitis, etc.) who want their "z-pak" or whatever else their primary doctor gives them the second they get a sniffle.

This problem is not, however, specific to urgent care centers. Urgent cares are just the most accessible. Most medical providers give out antibiotics like candy. As mentioned in other comments in this thread, it's all about patient satisfaction. If they leave happy, you're better off than if you followed evidence-based practices. It sucks.