And if they pay you money, and then you don't retire, under what contract clause would they terminate your employment?
Wut?? Your employment would effectively end on an agreed upon date THAT HAS NOTHING TO DO WITH YOUR RETIREMENT!!!
The vast majority of retirement eligible employees who (wisely) choose to accept the buyout will put in their papers the same day that they receive, review and accept the buyout offer. Care must be taken to select a retirement date that is after their voluntary separation date. The buyout will give them a cushion until their first pension checks are direct deposited.
Those with unique situations, such as having the YOS but not the age, have a lot to think about before accepting the buyout. Personally, I would take the buyout, freeze my pension, cut grass for a year or so and then unfreeze my pension.