There are measures that employers can take to protect employees and attendees at these parties. For example, employers may choose not to serve alcohol, or have less alcohol available, via a drink ticket system or otherwise.
Other actions can also prevent disasters, such as choosing not to hang mistletoe, avoiding dancing, hiring security or staff to keep an eye out for individual welfare, and making sure that staffers can invite spouses and family members. Increasing the amount of food that is available is also something that several employers are doing at these parties in order to ensure that everyone is well-fed.
Employees and attendees drinking and driving home is another serious liability concern. Make sure that someone is responsible for monitoring consumption and ensuring no one is driving home if they are unable to do so safely.