Even without Flock cameras, you almost need a pre-2000 vehicle to be invisible. Guessing on the year, but every vehicle in probably the last 20 years is trackable...
True, unless you have a cell phone inside that vehicle.
Dunno where the “stop” will be. There’s an awful lot of stuff folks choose to pay for that makes one fairly traceable, especially now that most new cell phones have satellite communication capability. Satellite radio, satellite TV (I’ve seen the ‘em on campers and ice houses), InReach communicators, anytime your phone pings an available WIFI whether you connect or not, and of course any form electronic payment you’ve ever used.