Look at the ceiling in most shops, lots of shop façades, all of the S-Bahn and U-Bahn trains, lots of railway stations and similar. It adds up. Semirelevant di

Look at the ceiling in most shops, lots of shop façades, all of the S-Bahn and U-Bahn trains, lots of railway stations and similar. It adds up. Semirelevant digression: A few years ago someone found that in Munich, the shop façade cameras covered every meter of the main pedestrian street (Hbf to Marienplatz). Not planned by anyone, it was just that each shop added a camera to watch over its own expensive display window, and there are shops everywhere there. Now the government is proposing a new law giving the police real-time access.