Free booze or not, if a drunk employee injures another employee, that person can claim benefits from the company. If the drunken employee drives away from the party and kills or injures a third party, the company may be held liable the same as any other social host or the restaurant bartender.

As a manager, your job is to keep employees safe and prevent accidents. Be careful not to push alcohol on others. Serve as a good role model by monitoring your own and your employees' drinking. If employees seem visibly intoxicated, you shouldn't allow them to work or drive. Call a cab if you have to.

When Employees Appear To Be Under the Influence at Work
First, be very careful about making judgments about the causes of anyone's incapacity at work. Many other kinds of medical conditions can mimic alcohol or drug problems. Your job as a manager is to focus on performance. If you see performance problems, instruct the worker what proper performance looks like. You have to be very cautious about accusing anyone of being under the influence of drugs and alcohol because doing so could be considered a violation of privacy.

Workers have a right to keep their private life private. If they have drug and alcohol problems that are serious enough to require medical attention, that may lead to a leave request or a disability claim.

When you see someone behaving in a way that leads you to suspect alcohol or drug use, figure out how it interferes with individual or team performance. If it doesn't interfere with individual or team performance, STOP! Why are you addressing this? You need to have a business reason to do so.