It is not dangerous to freeze and then thaw potato salad, so yes it can be frozen. That said, the results of a frozen and thawed potato salad are less than palatable.
Potatoes, unless they are shredded, do not freeze well. They undergo radical changes in texture and taste when frozen. In the case of potato salad there is also the mayonnaise and other ingredients that do not freeze well. When frozen, the liquid ingredients tend to separate from the solids and when the salad is thawed, the result is more akin to potato salad soup than what it started as. A better option is to simply refrigerate the salad for a few days if it is required before an event. There is no long term storage method for the dish that works well and it is better to purchase or prepare fresh.