I work in a hospital and see this extensively every day. Considering the venue its a little disconcerting, yeah? Doctors (med and psych), nurses, social workers, physical/occupational therapists, almost every day I can see one of them answer a question in another disciplines absence or speak with certainty about something outside of their field. Sometimes people think they know. Sometimes theyre afraid to say "To be honest sir/ma'am, I cant really answer that but will direct it to someone who can". Even if they are correct it's still dangerous. I'm a social worker and I couldn't imagine answering a medical question. Even if it's something common or that I'm certain of, you won't catch me in a professional setting talking out of my ass. I have no problem saying "I don't know" to a stranger.