Probably so. Of course, the question this begs, at least in my mind, is not one of, "Why aren't these people in prison?", but rather, "Why does anyone go to prison over something so innocuous?"
Granted, you can definitely engage in forms of trespass that are much worse than this, but for something like this situation, which was promptly handled, had no major ill effects, and was responded to in a way that indicates it truly was a mistake, I don't see why anyone should be up for prison time, whether as an individual or a part of a company.
Leaving it running for at least 2 weeks is not exactly promptly in my book. Even putting it in the release code disabled, without notification, is shady as hell. The forums are apparently riddled with complaints about gpu problems, including dead graphics cards on machines running the bitcoin software. While it's entirely possible it's pure co-incidence, it's also entirely possible they damaged thousands of dollars worth of high end graphics cards - which given they can easily cost $500 a pop, wouldn't take many. Consumer grade GPUs aren't designed to run full throttle for weeks at a time. Especially if, for example, a gamer has a manual fan control so they can shut up the half dozen case fans when idling, and ramp them up when they start a gaming session (I use this exact setup). A couple of generations back, I fitted after market copper heatsinks and fans to my GPUs to improve cooling at lower fan speeds, but the downside was they had to be manually controlled via a rheostat, so if something like this had been running without my knowledge it could easily have literally cooked my gpus without me being any the wiser as I ramped them down when to cut noise I was just browsing slashdot et al. Those cards are still trucking in a friend's machine several years later, incidentially.
Criminal damage in the course of trespass for profit? Seriously bad judgement, and really not funny. Worth jail time? No. Worth some real consequences? Yes.