My mom is basically a Republican (although not registered), and my dad scored "Centrist" on the WSPQ (is that just code for "afraid to commit"?).
The funny thing is, he's followed my libertarian arguments and agreed with me on most issues, but he balks at calling himself libertarian for some reason. He says, "I'm an independent - I just want the politicians to leave me alone. I don't agree with the Democrats' commie social programs, and I don't like the religious right dominating the Republicans, telling everyone how to live their lives and invading all these foreign countries. So whatever that makes me, I don't know."
It makes you a libertarian, Dad. Embrace it! (I'm still working on him...)