Texas has always taken a lot of pride in itself and Texans in themselves. Sometimes maintaining a sense of exclusivity while playing up our friendly attitude. Jokes like "Welcome To Texas, Now Go Home" for example.
You've seen them and, being unaware of this law as I was, probably didn't even bat an eyelash. Although, you may have raised an eyebrow. They are blatant about it, almost intentionally trying to draw attention to their flagrant lawlessness.