Does group insurance do post-claim underwritting?

No. Group life insurance operates on the principle that everyone or almost everyone (a percentage specified by the insurer) in the group must participate. This negates "anti-selection" (the tendancy for only people in poor heath to get insurance) and therefore eliminates the need for most underwriting. Companies usually base prices on the group's previous mortality experience (the number of people that died per age group, per year). The only time a life insurance company would really underwrite a group policy is if the group had limited or no previous mortality records (no previous group insurance). Completely aside from that, a company will investigate any claim they suspect of being fraudulent. For example, almost all GROUP insurance polices exclude death as a result of suicide, so if someone overdosed on a medication the claim would almost certainly be investigated.