Under the law, who can potentially face consequences for over-serving a customer who then causes harm?

Depending on the jurisdiction and its dram shop and server-liability laws, the server who made the illegal service, the establishment (licensee), or both can face consequences when an over-served customer goes on to cause harm — such as a drunk-driving crash. Consequences can include civil liability for damages, fines, criminal charges, and loss of the server's certification or the establishment's license. This shared exposure is why both individual servers and businesses take responsible service seriously. Knowing who bears the risk underscores the importance of lawful service.