The same thing has been done in Louisiana. The cops see (mostly) a latino, or an African American, then they shake them down. Many legal latino's carry cash to take back to their family Mexico, and the cops say that it is drug money, and take it.
Also read about one woman, (not latino or African American) from the West Coast, who had her money taken while in Louisiana. Last I heard, (a few years ago) she still had not gotten her money back.
I tell all my friends that when they travel by car, DO NOT carry large amounts of cash. When you need cash, go to the ATM. I travel often, and I only carry enough cash to get to my destination. I can get more at the money machines. It is too easy for the police to say it is drug money and take it. This goes for any state, not just Texas and Louisiana.
As an added note, I've seen the following in both North Carolina and in Louisiana. Driving down the Interstate, and you will see a temporary sign stating that "All vehicles MUST STOP, Five Miles Ahead, for Illegal Drug Inspection". (The one I saw in Louisiana had two signs a quarter mile apart). Well, guess what, no vehicle inspection five miles ahead, however a half mile, or one mile past the sign, there will be a rural exit. Any car that gets off at that rural exit, gets inspected.
Cops think (rightly so) that those with drugs will see the signs, and want to exit before the mandatory inspection. At the one in North Carolina, I could see the cops waiting, as I passed the rural exit. They are not dumb.