Last Update: March 30, 2019
For a complete writeup on charging station etiquette -- Charging station etiquette - effectively sharing limited electric car charging resources
It is out of line and inappropriate for an electric car owner to take the law into their own hands. Some believe they should slash the tires or otherwise damage the car that's blocking the charging station. That is illegal. Others believe in the right to park behind the car blocking the charging station. That is likely to be blocking a lane of traffic, and is therefore illegal. Others point to instances where firefighters have broken car windows to route a fire hose through a car blocking a fire hydrant. That's an interesting analogy, but fire fighters are literally facing an emergency situation and have to do what they have to do. An individual breaking someone car windows is guilty of vandalism or breaking and entering.
Don't be that person. Be the smart person.
J1772 extension cords
Instead consider these products
They are J1772 extension cords. They are designed to plug into the charging station cord and extend its reach.
With a blocked J1772 charging station, there is probably a nearby parking stall that is unoccupied. Then, you pull this cord out of your trunk, attaching it to the charging station cord, and plugging it into your car. With luck it will reach and everything will be fine.
The JLong has a particularly useful feature. It supports being used with a lock, so that the cord is firmly attached to your car and is therefore unlikely to be stolen.
It is possible to leave a note on the car blocking the charging station.
It is possible the driver of that car simply does not know the pain they are causing.
It is preferable to be kind rather than vitriolically nasty.
On the charging etiquette page are some preprinted cards useful for either a) instructing someone about charging station etiquette, or b) requesting charging assistance
The owners of the facility should be notified of the problem. A parking lot owner probably doesn't care about electric car owners. But they might start caring if electric car owners speak up every time the charging station is blocked.
Again, being nice but firm is the best approach rather than flying off the handle with anger.
In most areas it is illegal to block a charging station.