Wow, that's an interesting query. Yes, I'd have to say you COULD get arrested at a mortgage closing. It's never happened at any of my closings but I've heard stories in training sessions.
For instance, a title agent became suspicious that the ID presented in the closing was fraudulent. It's normal for a title agent to carefully review ID - we're trained to look for fraud. It's also normal for the title agent to excuse themselves from the room to make a photocopy of the ID. In this case, the agent took the ID to another member of their staff who continued to make inquiries into the situation while the closing continued. They discovered that the parties in the closing room were indeed up to no good and the police were called and yes, they were arrested.
I have been in closings in which we took precautions against potential physical violence. This doesn't happen often but sometimes there is one person who appears explosive. Once I sat before a closed door in a real estate office behind which sat the husband and son of the real estate broker. The sellers were in a nasty divorce and the husband had a history of violence. He did nothing more than call the the wife's attorney a nasty name and sat there growling. Thankfully we didn't need to call the police.
On another note, I put in place a policy this year that if I find criminality in the public record I take extra steps to protect my closers. If we have someone with a criminal history, we close only in public places - never in a private home.