THere is no simple opt out!
When HepB was introduced to our county 15 or so years ago, my pediatrician 'suggested' I allow our two children to get it.
I had the choice to say...'No'.
Sometime in the intervening years, it became mandatory...and pediatricians in this county....even when a baby is still in the hospital having just been born....will not accept the child as a patient unless he/she comply with the vaccine rules....including HepB.
Not knowing the laws in Texas, I can't speak to what their law says currently. But your point is well made. "Opt out" isn't so easy as people try to make it sound.