Several agents I asked confirmed the same thing. $400 voucher good for a year to be used like cash, since I would be delayed by more than 4 hours. Supposedly they would pay for a hotel, ground transportation to their hotel, and meals. Passengers paying cash would also receive a refund of this portion of their itinerary, or half the roundtrip price. Passengers on an award ticket, like me, would get half their SkyMiles back. But I wouldn't arrive in JFK until late the next day, I had things to do waiting at home for me, and I had an assigned seat. So the gate agents agreed that it's in my best interest to board as originally planned. In the end, the gate agent got 3 volunteers and 1 involuntary.