We did investigate this but found that USB authentication was unsecure and unreliable without an expensive ‘iLok’ style USB device, which then has the potential to be broken or lost.
Hence the method of Add-ons being installed on individual units using the unique DNA, and once installed are unaffected by firmware updates or hard resets (and cannot be removed).
So Add-ons ‘belong’ to the desk, as opposed to plugin licences that might belong to the engineer.
You are correct that many engineers have shows which include Add-ons, and would therefore prefer a fully upgraded house or rental desk. This is why Avantis Add-ons are provided as a single dPack (it either has it or it doesn’t) and why we recently introduced the ‘All Add-ons V1.6’ bundle for SQ.