Body armor. Showing up with weapons is normal in some places, including Texas. Body armor, not so much. It's the body armor that's the real evidence of preparation.

P.S. Also, there's no inconsistency. Simply apply basic logic. You have the right to be armed. You do not have the right to shoot at law enforcement officials; that's a felony. Nor do you have the right to plan ahead of time to commit a felony, including shooting at law enforcement officials.

Is wearing body armour illegal?

You're shifting the goalposts rather a lot here; at first you said that just bearing arms (allowed by 2nd amendment) and wearing body armour (not forbidden) was proof that they're 'clearly prepared ahead of time for violence', and now you're saying that they're simply not allowed to shoot at law enforcement, which no one disputed.

Which is it? And why don't you apply that standard evenly?