The way he explained it to me was if he took the early retirement he would receive the pension, if he had stayed and gotten laid off he would not have gotten the pension.
This is nothing new for them. My father started at IBM in 1968, and was forced into "voluntary" early retirement in 1993. He at least got to keep his pension, but if he hadn't gone voluntarily and opted to stick it out like some of his colleagues, he would have been let go in the following months and lost everything.