I don't doubt that Texans take their boots seriously and that it is customary to wear them with dinner clothes. However, dinner clothes weren't developed with cowboy boots in mind. It is an extremely harsh juxtaposition. After all, the dominant theme of black tie is elegance through simplicity. Dressy cowboy boots in exotic leathers are hardly simple. Thus, they are an aesthetic disruption to their adopted context. And that's to say nothing of having to widen one's trouser legs to accommodate them, another disrupting effect. It's tragic to ruin what was so inherently and purposefully streamlined for the sake of an ill-placed regional affectation.
If Texans want to wear cowboy boots on occasions that would otherwise call for black tie, I think they'd be better off coming up with a new kind of complementary attire. That seems the gutsier route, and thus the more Texan one, anyway.
I thought the boots discussion was largely about pairing them with suits, not formalwear? I know that Bush had the black tie and boots gala but I feel as though the "customary in TX" idea mostly applies to them being worn with business suits. But maybe I skipped some of the relevant posts?