jpod, thank you for your further observations.
For the reason you suggest and some others, I tell plan administrators to read the death certificate, which often has some information about illnesses and causes of death, and sometimes about who called in the death.
Likewise, we read obituaries, which often name a spouse, children, other relatives, friends, and others, and mention personal details about the decedent. We’ve often quickly discerned a claimant’s false statement from what was described in an obituary retrieved from a first page of Google results.
Some steps you suggest, while they might be useful with a small-business employer’s plan, might be inefficient, impractical, or inapposite for a plan with tens of thousands of participants, especially if claims-handling is mostly outsourced.
For the plan that’s the subject of this discussion, the default beneficiary is the participant’s estate. If that provision applies, the plan pays the estate’s personal representative (and need not know anything about who takes from the estate).