You'll definately want to read post #48 before leaving for Texas.
Getting someone's attention by lightly touching them is not the same as poking someone in the chest or grabbing their arm. No judge in his right mind would apply the statute to this case.
The operative word under the statute is "reasonably." In most cases it isn't reasonable to conclude that a mere tap on the arm would be perceived as offensive. The prosecutor has to prove all elements beyond a reasonable doubt. Ties go to the defendant. Result: acquittal, followed by a suit for malicious prosecution.