What are the options for the buyer?
And what if the insurance claim and IMEI block were initiated a few months after the purchase? What if the seller is not the original owner? (could be a thief or a lucky second owner). In my case it was Vodafone's f'ed up and the seller/original owner was very helpful to sort it out.
In hindsight are there any measures to mitigate this risk?
Asking seller to provide an original receipt?
Bring the working phone to Apple store / Samsung store to register as the owner? Would it work if later it was claimed stolen?
How do you figure it is vodafone's fault?