Perhaps this is not universally true, but I believe in every case I've looked at, the spouse of the pensioner is required to sign a release form when the pension begins stating that he understands the terms of the pension. The exception occurs when the pensioner elects to take the reduced pension that remains the same for the widow(er) when the pensioner dies. In that case, the signature of the spouse is not required.

The place where it can be sticky is pensioner begins taking pension and chooses own lifetime only for distributions. Pensioner later marries. It's usually too bad if pensioner predeceases spouse because that will be the end of the pension.

rad