How much does an electric car cost to charge?
Now, if you count in the time cost for law enforcement (15 hours in jail, the petrol from picking up the suspect and re-delivering him home, multiple hours of paperwork), the cost of enforcement is likely to be tens of thousands times more expensive than the value of the "stolen" goods. But hey, the US aren't exactly known for applying common sense in law enforcement. And anyone placing a open wall outlet without a lock on a totally public area (a parking lot!) is not in any position to whine later on.
The classic example is, your neighboring tribe steals a goat. You could chase after them, but then there'd be a confrontation, and some of your people would probably get killed. It's not worth a life for a goat. But then next week, and the week after, and the week after that, another goat is stolen. Each week the same calculus holds: one goat is much less than one life. In the aggregate, though, you've lost dozens or hundreds of goats. Too many.
On the other hand, you can respond to the theft of a goat disproportionately. You can chase after the thieves, confront them, beat them, kill them. Some of your people will die, some of their people will die. Next week, they don't come back to steal a goat. A goat isn't worth one of them dying over, either. Your tribe has a reputation of "not to be messed with", and the thefts stop.
It may be the horrific underpinning of all types of warfare, from gang to nation-state, but it is pretty rational, and provides a solid reason to spend a thousand bucks prosecuting a 5-cent theft: it's not about punishing the 5-cent theft, it's about preventing the future aggregate theft of thousands of dollars.
This is one of the reasons why there's movement to undo the mandatory minimum sentences and harsh sentencing trends that have arisen in the past 20 years - because it doesn't actually deter crime.
For this particular case, if the school had simply put up signs saying the outlets are monitored and you'll be fined for any misuse would have probably done the trick without resorting to actual police intervention.
I would like to clarify the blurring of two disproportionate costs.
The first is the cost to the criminal. Assume for the sake of argument that in this case we're talking a trip to the police station, a $50 fine, and 10 hours of community service. Absurd for a $0.05 theft of electricity, but a limited sort of absurdity. The criminal is made to pay a disproportionate amount in restitution for his crime.
The second is the cost to the society. The cost of having a police man arrest someone for a $0.05 theft, jail him, take him to court, and supervise the community service. Hell, the cost to cash the $50 check for the fine is probably more than $0.05. The society pays a disproportionate amount to prevent a $0.05 crime.
These two separate costs have two separate objections. The first violates our inherent notions of fairness; the second raises the question of cost effectiveness.
Edit: Which is why fines are used for minor offences they dramaticly reduce the cost of enforcement. And really refilling an electric car is about the same cost to society (1-2$) as someone not paying a parking meter so the response should be vary similar.
A parking lot is a public amenity. (Some lots are restricted to authorized people or even charge for use, but that's beside the point.) That amenity often includes anywhere from one to several dozen bright electric lights, that are on from dusk until some time after close of business, or even until morning. No one is charged for the kWh that lighting consumes, as that is understood to be part of the cost of operating a parking lot.
I don't agree that plugging into an open outlet is stealing, and I believe that the charges (pun not intended) will be dropped excepting a verbal wrist-slap to not do it again. Perhaps in the future the school will either restrict access to the outlet or provide a sign that forbids electric vehicle charging.
I don't think I've ever seen one of those receptacles made available for public use in parking garages. Presumably it's something from a colder climate than where I live. Note that the incident we're discussing happened in Georgia, where such things are not needed.
If I leave a stack of $100 bills sitting in front of my door and you take them, that is theft and you can be prosecuted and I most certainly have the right to complain about it, even if I really should have kept it more securely.