Someone just got busted for doing that , was a top whale with his mag in the 8000's and I hope you are next.
Someone also accused that other someone of far worse things in the same mail. It wasn't true of course, but the damage was still done.
Not paying for hardware or electricity does not automatically make you a mag thief.
I'll add that it's fine to have a discussion about ethics as far as using hardware or electricity that you technically didn't pay for. I want people to know that the Gridcoin community cares about being honest. But yeah, there's a difference between making use of idle time on a couple computers in your office, and subversively running a large scale mining operation w/o permission or consent.