This actually doesn't seem that far fetched. Ex-drivers who are angry and have plenty of time on their hands out at night picking the RFID tags out of stop signs.
Another scenario is more of a slow and steady war. I'd expect that autonomous vehicles will occasionally be alone and unoccupied, which makes them a tempting and defenseless target. You wouldn't even need to do any physical damage to disable them - just a little electrical tape over their sensors, or some chocks under their tires. Soon, the autonomous trucking cos have to employ some of the ex-truck drivers to go around re-enabling their vehicles. And of course, those ex-truck drivers are in cahoots with the disbalers. That could certainly drive down their savings on labor costs.
Another scenario is more of a slow and steady war. I'd expect that autonomous vehicles will occasionally be alone and unoccupied, which makes them a tempting and defenseless target. You wouldn't even need to do any physical damage to disable them - just a little electrical tape over their sensors, or some chocks under their tires. Soon, the autonomous trucking cos have to employ some of the ex-truck drivers to go around re-enabling their vehicles. And of course, those ex-truck drivers are in cahoots with the disbalers. That could certainly drive down their savings on labor costs.