|A plate belonging to someone from Klagenfurt, in the state of Kärnten|
If such a scheme were run in the UK, the first two letters of the licence plate would indicate your place of residence. For London, it would be a London shield symbol plus a borough code - say LA for Lambeth, WE for Westminster, BR for Bromley and so on. Any 'county lines' drug dealers here have a very hard time - but that's not all.
Country areas are naturally suspicious of outsiders even in good times, and the Wuhan virus has magnified mistrust of any vehicle with a 'foreign' licence plate - and by foreign, I mean a vehicle from a neighbouring district, never mind out-of-state vehicles or the Satanic chariots carrying the evil W for Vienna. Believe me, after a while non-local vehicles stick out like a sore thumb in the supermarket car park - and you can be sure if a car with plates bearing the shield of Tyrol and LA code that includes Ishgl, the seat of Austria's après-ski contagion, were spotted there the store doors would have been locked shut.
I'm fascinated to learn how the locals will cope with the end-of-lockdown dilemna. They will be riven between mistrust of the outsider and the welcoming of the critical summer tourist Euros. It will be fun to watch.
And second-homers in the UK can be very grateful for the anonymity of UK licence plates.