Anecdotally yes it could be dangerous. My ex has BP disorder and hid it from me. After about a week of super erratic behavior he woke me up in a complete panic to tell me I had to call the FBI about some nefarious plot he had uncovered. I didn’t know what I was dealing with, but could tell that he was super messed up so I thought it was a good idea to debate the logic with him. After going a few rounds with me, dude lost it started screaming and breaking dishes and threatening me. I had to lock myself in the bathroom and call the cops, he pounded on it mercilessly until they arrived. He didn’t hurt me, but he damn sure could’ve. I wouldn’t fuck around trying to talk a stranger out of their delusions unless I was real sure shit was going to go my way if it came to a struggle.