Not sure how sony is strict on looking at receipt but when u registered the warranty online under mysony account. U need to input your serial number and purchase date. Consumers have voiced out that sometime they have received their sony products as a gift and unable to produce receipt. U can stated as a gift.
I went to other service centres like to service my acer laptop and engenius router. both didnt bother to look at my receipt cause they said they have my product serial number.
Then I got it today, I can don't register also. If something happen or spolit then I register the current date lo.. If not 1 year later i want to sell, then I can register under 1 year later date as purchase since no receipt ma.