Or they wait you out. If you have talent and ask for the RIF they may just wait you out given that they know you can get another job. What's in it for them? Milk some more productivity and avoid severance/risks. If you just give up on the job they can also fire you with cause, so be careful after volunteering if they reject you. Also helps them avoid clawing back severance if they catch you double-dipping and employed elsewhere soon after. Not sure how aggressively WIN pursues that but wouldn't put it past them, severance isn't an earned right its given (don't shoot messenger).
The voluntary severance packages should be brought back along with other options like reduced pay for reduced load (ex; 4 day weeks for a couple quarters). Lots of folks would jump on that but these programs aren't free there is a cost to administer them, HR is probably already threadbare given the tone of this board regarding internal practices.