Rich, I agree that "the wrong cop stopping you" can be a pain in the rear for even the law abiding large vehicle driver. Following some the of links above I checked out the Texas CDL manuel ... yep the same thing I studied in the DPS office chair prior to taking my Class A written test ... and clicked on a practice test or two. Admittedly, not all of the questions are this basic, but I got a kick out of this one:
5. After inspecting mirrors and windshilds for cracks, dirt, illegal stickers, or other obstructions to your vision, you should:
A. Look in the mirror to see how good you look.
B. Clean and adjust as necessary.
C. Not worry about any of it.