They could just share UCNs instead. SSIDs cannot be stored (or shared). But UCNs would function exactly like SSNs in the current system. SSIDs just exist to "

They could just share UCNs instead. SSIDs cannot be stored (or shared). But UCNs would function exactly like SSNs in the current system. SSIDs just exist to "wrap" UCNs, they prove that you have the current SSID for whatever person you're claiming to be (kind of like a poor man's password) and make it more difficult for thieves to re-use the UCN number trivially (you'd have to be an insider to enter a UCN, outsiders need the SSID). The reason to stop people storing or sharing the SSID is primarily so SSIDs themselves don't become the SSN replacement. Companies might get lazy and instead of converting the SSID at the SSA, they instead "cache" the SSID->UCN conversion in-house or worse just use the SSID directly. You have to make SSIDs ephemeral. UCNs and SSNs are static. UCNs can be stored/shared, SSNs get outmoded eventually, and SSIDs are short-lived no storage-sharing numbers that provide the UCN.