There may be modes that users can place on themself to give some protection. For example, freenode has a +g mode that keeps you from seeing private messages from people unless you use the /accept command to add them to your list, or unless you message them first.
/mode mynick +g
Also there's mode +R that can be put on your nick which makes it so you can't see queries from people who are not identified to nickserv
/mode mynick +R
