1. Your ISP can see if you're using TOR, if you don't configure bridges or use a VPN.(Original post by Zereux)
Not sure if that is sarcasm or not, but it is in fact a true story. I believe they managed to track me down because I downloaded something off a website by accident. Can't be certain though.
2. Using TOR is not a crime and the police can't do anything about it. Granted you'll probably end up on a watchlist, but they would never threaten you about it.
...for the 2nd time this year