The headline makes it sound like someone pranked them (at least to me) but the reality is a bit different:
The family’s smart thermostat was installed a few years ago as part of a new home security package. Many smart thermostats can be enrolled in a program called "Smart Savers Texas." It's operated by a company called EnergyHub.
The agreement states that in exchange for an entry into sweepstakes, electric customers allow them to control their thermostats during periods of high energy demand. EnergyHub’s list of its clients include TXU Energy, CenterPoint and ERCOT.