I don't believe it. If they're impulsive enough, lacking enough vision, and low-effort to want to rob a cash register, there's 0 reason to take time to figure out how to disable multiple power substations to do it. If they were trying to be smart, surely they know that destroying power substations would really up their legal risk if caught.

My bet is an analysis of their phones/computers will be very revealing, and that they're selling this "robbery" story to try and avoid more serious charges.

Then again, maybe they're stupid in just the right ways.