It's not too big of a leap to imagine a world where a person could immobilize a car at a red light with the plug cut off from a public charger. Wall up to a stopped car, open the hatch (maybe it needs a pry bar) and put the dummy plug in.
Sounds like a lot of hassle. If they want to immoblise a self driving car they just stand in front of it.
Why carry a plug cut off from a public charger when you can just stab the tyres?
Use the pry bar to smash the window and open the door. Not open the charging port.