This assumes that stamps are scanned when sold, to tie their barcodes to the purchaser. That may happen. It may not. But clearly the more scans a stamp gets increases the tracking resolution for a given piece of mail both after AND before mailing. This "before mailing" part is new and opens the door for a much higher level of surveillance.
But if you think about it for more than ~10 seconds, you remember that stamps are sold in packs of 4-8 at least. They're also often sold in sheets of 50+. All this makes individual scans painful.
So you want to play the devil's advocate and make more assumptions; say, for example, "every stamp could trace back to its original pack, so only one of them needs to be scanned". But if that's the point of this panopticon move, then why put the barcode on the stamp, rather than … the pack itself?
Because you know what always gets scanned? The product's barcode. If I wanted to track people who buy stamps, I would create unique EAN13-compatible barcodes for every single pack sold, always start them with the same number space + some digits for actual different products, and voila, somewhat backwards-compatible, unique tracking on all those stamps without having to deploy a barcode on every single stamp, implement a swap-out scheme, etc.
Of course, maybe someone at GCHQ is reading my comment and thinking "fuck, why did we spend so much money on this scheme again?", but somehow I doubt it.
I think you missed the part where I’m making the argument against this being even sort of practical as a surveillance tool.
If anything all the stamps would have two ID in the barcode. One linked to the sales location (always the same) and one as a counter for the individual stamps. That would avoid having to scan every single one.
"Who purchased this stamp?" is a very hard question to answer in their current (essentially fungible) form. Adding barcodes makes this much easier.
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so reselling stamps is not an option ?
> This card was used to buy this stamp and we have this face on camera doing it.