Out of the 600+ that are eligible, how many are commuters, that are dissatisfied with their schedule and have other ways to make an income?
Senior pilots, pilots who live in base, or don't have good exit options are obviously going to stay. But a I bet a decent number of older commuters can get a corporate or part-time job in their hometown and use the lump sum to offset the pay cut.
Call me crazy, but I wouldn't be surprised to see 100+ take it.