Yes, many times. Once you explain what a Tor exit node is, you can't be convicted of downloading CP or whatever the anonymous user did, because you quite plausibly didn't do it. However, a verdict of innocence only happens after your life was already ruined by the process of getting to that point...

Some countries like Germany have strict liability, where you must pay a fine for any copyright infringement that happens on your connection unless you register yourself as an ISP yourself. If you're not sure, consult a lawyer to make sure you're not in one of those places.