I wondered about that. I know TX has outstanding gun rights laws, but this is beyond what seemed legal. IF this kind of shooting is OK, then look for lots more shootouts, in the name of robbery. Whether it is on not. All people need to do is shoot someone and say they were trying to rob them. Drug deals gone bad, etc.
No need to wonder about it. Read the actual statute in Chapter 9 of the Penal Code, linked in a post up a couple. Read especially sections 9.42 and 9.43. Deadly force is authorized even to protect a third person's property. No threat is necessary or even mentioned.
We don't cotton to thieves 'round these parts.
That strategy would be a very risky one to try to carry out. It would be best if the shooter had corroborating eyewitness testimony to the shooting from an individual or individuals not associated with him.