When they offered the Perl course at my school recently, the same thing happened to me. One of the students who's working closely with the teacher who got the course accepted looked at me and said that -- for me -- it would be an "easy A, since you're the Perl guru around here".
My first thought was: Boy, is this place in trouble if I'm the Perl guru around here! My second thought was an attempt to think of anybody else, anyone, who I could even attempt to talk Perl with. Nobody came to mind. It makes sense, unfortunately -- school administration is made up of the kind of people who would never come in contact with it, there's really only maybe five staff members who can do anything sophisticated with a computer anyway -- logically, nobody would hardly have heard of Perl.
I'm guru by default, it would seem...
You are what you think.