required attendance at weekend event

A reader writes:

My organization is planning a large anniversary party that will be held on a Saturday (non work day). Employees are expressing concern if it is mandatory they attend, as there is another event in town occurring that night many have already purchased tickets for. Can our president make it mandatory employees attend? There is also concern of retaliation in performance reviews, end of year bonuses, and yearly raises for those who do not attend, is this legal? We are a small business, so full time employees who do not attend will be noticed at this event. Please advise.

Yes, it's legal to make it mandatory. It's also legal to raise it in performance reviews and so forth that you skipped an event you were asked to attend, or decide that you don't show the expected engagement in company activities, etc.

But that's a different question than whether it's smart. If employees weren't given a lot of notice about this, it's not smart -- because employees may have other plans, may not even be planning to be in town, may need to arrange child care, etc. If a company is going to require attendance at something outside of normal work hours, it should give a ton of notice. But again, there's no legal requirement that they do so; only a practical and humanitarian one.