Sure, a technical solution can and, probably, will be looked at at this point. That said, your blithe assumption that it's twenty minutes of work does belie an ignorance of how this stuff works. And you're castigating them for not putting one in place when it hasn't been, to the best of my knowledge, a significant issue in the past. Had there been a previous rash of SIM card thefts, something very well may have been done in the past.
In other words, I am reasonably certain that you have decided on your conclusion and are working backwards from there (see your nonsense about "cackling maniacally"). I am rather certain that this is an unacceptable way of looking at business or law.
As for whether the fine is equitable--well, let's see:
* The overage charges were part of a legal contract and agreed to by both consenting parties.
* An third-party agent--the thief--unlawfully incurred charges on behalf of the power company (charges that, one can presume, would have been an acceptable, if regrettable, cost of doing business had they been incurred, for example, due to a software fault in their power meters).
What do you think should happen? Do you think the telco should not be paid according to the agreement for their account? Should the power company pay it despite the SIM card against which the charges were levied being stolen? Or should the fine be levied against the thief who committed the wrong?
As is likely apparent, I am of the opinion that the thief should be forced to make good on her damages. They are not illusory damages; _someone_ will be made less than whole if the thief is not expected to provide compensation. And, no, I don't expect her to pay it back. But it is her obligation to make whole those she has wronged. Doing otherwise is neither reasonable nor fair.
The unforeseen cost of her action is quite high. That's unfortunate. But, at the end of the day: if you commit a crime against another person or entity, you _are_ culpable for the results. If she did not want to be held responsible for the results of stealing another's property, she shouldn't have stolen it.