How much time does it take to verify? If the insurance companies do this verification even 1/10th as aggressively as they do their "marketing" (intrusive phone calls included), I don't think they really need 5 years.
Almost all policies have a window of time, so that if I buy the policy today, I can stake claim only after 6 months and not before that, or something similar. I say that the "time for verification" should be made same as this time.