I disagree with you on this one.
I think you're right about the supply chain, jimbo, but I also still think people would lie to get to the front of the delivery line.
I definitely don't want Tesco or Aldi having to determine who should or shouldn't get priority delivery slots.
I would image that the government probably supplies a hash value (one way encryption) of each of the emails, then the grocery stores hash the emails of all their customers and then compare the hashes.
Spare me your IT mumbo jumbo, nerd. Where's my toilet paper delivery!? 😉