Oh my God yes. There are some really great ones too but man are a lot of them complete loonies on stuff like this. Some of them still don't spell correctly on their resumes.
This is a favorite too. It seems to happen more on the public health area than the hard research studies (physics, biochem, etc) because I think most grad students in those areas know they're in for at least a decade as grunts--masters/PhD/post doc. Also they realize that a lot of professors don't have more than a couple students as "staff".
As an aside it bothers the shit out of me because I see public health and dietetics people stepping waaaay out of their lane on matters they don't really fundamentally understand. I've seen a lot of them try to speak with authority on topics definitely deeper than they can swim in.
Naturally as someone who has many deep interests I don't consider it bad when a person expands to new lanes or fields. I do really dislike it when they try to be experts on it right away though.