> so there absolutely should be investigations into people bypassing the law
No, there really shouldn't have been an investigation. This was evil, wasteful, and above all, truly fucked up.
She didn't "steal" a vote from anyone. She cast a provisional ballot, after asking permission. There doesn't need to be an investigation- just check the facts, and deal with her provisional ballot as necessary.
At my college, we had a guy walk across the stage at the graduation ceremony for the school of engineering. But he wasn't in the school of engineering; he just found there ceremony to be at a more convenient time, and assumed it was all the same. They didn't call his name, and nothing came of it. Because it was an administrative issue. What they didn't do, was throw him in jail for trying to steal an engineering degree. Because there was zero chance of that happening, and he wasn't even trying to do that.