Ahh, now see I'd consider that a ways beyond harrassment and more along the lines of attempted forceable entry.
The problem, of course, is that reaching in to retrieve your weapon once already involved in a situation leaves you open to attack while doing so.
I think this section of the penal code would be more pertinant to your question:
Basically, as outlined, it would be legal (and safer) for you to 'carry while pumping' so long as you pay at the pump. If you walk into the store carrying, you'd more than likely be violating the above statute.
IMO, this statute, coupled with the above quoted self-defense statutes listed by Texas Rifleman should pretty much cover you.
Also, a vehicle as defined by the TPC is a motor vehicle.
My advice would be to fuel up in the city - not in the boonies or outskirts. Gas prices are lower anyway.
