I rarely felt unsafe when I visited psych. patients at home in my previous home care job. Usually the clients view the nurse as a support person. They are often socially isolated and welcome the company, and the security of knowing that a caring person is checking in and making sure that they are OK. Home visits are voluntary-the client has a choice to accept visits or not, and if a client is becoming very paranoid, they usually will not open the door if they feel that the nurse is a threat.
In my experience, working on a locked psych unit is much more dangerous, because clients mostly tend to lash out when they feel trapped in a situation. Also, if I visited a client and felt that I was unsafe, I could leave the clients home, tell my supervisor, and another plan could be made. Perhaps the client needs to be hospitalized, or a visit by two nurses could be arranged. I don't remember ever having to do this. I am lucky in that I work for a great company (same one I worked for in the past)and I believe that they take safety very seriously.