I personally don't think it's a big deal... a degree is a degree and boy do we need teachers nowadays, u know... I had a teacher in high school that did the same and she was VERY well respected... I see no problem with it, Id actually like to do it myself... What grade would you like to teach?.
I am not sure about the answer to that question but I thought you should know that a lot of Universities are now requiring a minimum of a Masters. I have my Bachelors and teach at a University- one of the few that accepts Bachelors. I am now about to get my Masters because it seems like it is a must in this field. My discipline is Marketing and some schools even want a Doctrine!
I believe it was meant as university classes not as a university teacher...