Including people they want to keep? What if all the people they wanted to keep accepted while those they didn't want to keep stayed? Certainly makes no sense.

I imagine they don't extend the offer to specific people they want to keep.

I'm still not sure what the advantage to the company of an offer like this is versus layoffs where management gets to choose who leaves, unless they feel the "loyalty test" of deciding to stay is worth more than their own evaluation of employee performance.