Of course the appearance of a similarly ugly pair of pants is interesting. It could mean Northam went out on Halloween with an old friend of his, and it is Northam in the KKK costume, or it could mean that Northam borrowed the pants from his friend for his costume.
As long as we're all theorizing...
If there were all these school clubs or cliques, who's to say that they didn't all get similar pants for a nerd party or other such party prank?
-PJ