Really? Could you explain or show an example of a shop doing that?
As nostr:nprofile1qqsw4v882mfjhq9u63j08kzyhqzqxqc8tgf740p4nxnk9jdv02u37ncpz4mhxue69uhhyetvv9uju6mpd4czuumfw3jsz9nhwden5te0wfjkccte9ec8y6tdv9kzumn9wsq3yamnwvaz7tmsw4e8qmr9wpskwtn9wvql3tqm said, it is truly baffling that governments and politicians don't use digital signatures to prove the authenticity of their announcements.
Even my fucking grocery store cryptographically signs every sales receipt.
Discussion
Just look at any groceries receipt, there are pubkey sha and sig data on it. Many POS terminals are doing that by default.