...though once this kind of attack became common, the utility meter manufacturers started adding anti-tamper features like hall effect sensors that record the p

...though once this kind of attack became common, the utility meter manufacturers started adding anti-tamper features like hall effect sensors that record the presence of an unusually strong magnetic field near the meter equipment. You'd get some questions next time the meter reader came around and the tamper indicator was lit. Utilities have a lot of financial incentive to keep people from (at least blatantly) manipulating their billing.