Re: “… then there shouldn't be privacy issues...”
First I do NOT disagree that sharing tags would be a very useful feature. We own 4x tags ourselves and would indeed like to see this feature implemented.
However the “privacy” issue has to do NOT w/ you or your shared family “directly” but w/ the “relaying” iPhones.
= A bit of tech background: =
AirTags are pretty basic “beacon” devices with a bit of crypto added; they don’t contain GPS or have the “faintest clue” as to where they are located.
ANY passing-stranger’s iPhone that “sniffs” YOUR tag, reports the tag ID and THEIR phone’s location to Apple’s servers - via a message encrypted w/ YOUR public key (exchanged w/ the AirTag during “pairing”)
The “privacy protection” concern is that YOU can obtain YOUR tag’s location from Apple’s servers (which is actually SOMEBODY ELSE’s phone’s location) w/o you knowing who’s phone is doing the reporting OR being able to otherwise geo-locate that particular phone.
Further Apple can’t see YOUR tag’s location either. (All tag location decryption is performed by FindMy using YOUR private keys on YOUR trusted devices)
Restated another way … YOUR own phone today is reporting YOUR location along with the TagIDs of COMPLETE STRANGERS
Thru some clever cryptologic methods, none of the “strangers” can determine that it’s YOUR phone and YOUR location.
If so-inclined, a couple of even “deeper dive” technical description articles begin here:
https://support.apple.com/en-au/guide/security/sec6cbc80fd0/web
