Dairy Queen: Void In TX?

I just watched a Dairy Queen commercial on TV about the new all-american blizzard: red white and blue M&Ms in ice cream. Sound good. :-)
Then I noticed something strange. In the small print at the bottom of the screen:

“At participating stores only. Void in TX …”

Huh?
Wonder if Texas has on of the strange gun-toatin-red-neck laws where you can sell things in red white and blue unless it’s a flag. Hey, I’ve heard stranger things.