An official warning from a DOT cop is something very different from a general warning from a local cop and can go on your CSA 2010 score, but do not confuse a DOT warning with that of a local cop. I promise you, if you get a warning from a small town cop, a county sheriff, or someone else
other than a DOT or State cop, it doesn't go on your CSA 2010 score, or need to be reported to your carrier. It doesn't matter if you have a CDL or not. Even if the warning contains an "Equipment Repair Order" where you must show proof of repair to the local authorities, it doesn't go on your CSA 2010 rap sheet nor need to be reported to your carrier.
They can't do nothing about license plates, but one should check with the laws from other states when it's about tinting the windows.
Why? They can't do nothing about window tinting, either. Some states allow as little as 28% VLT (Visible Light Transmission) through the tint (Florida), New Mexico is just 20%, others like New Jersey allow no side window tinting at all. Kentucky is 35% VLT whereas Iowa is 70%. To an Iowa cop, when they see 35% driving down the road, like they did me, it stands out as being significantly darker than Iowa state law allows.
But like the cop said,
"Even though you didn't break any laws, I have to give you a warning to let my bosses know what I'm doing out here. When you get out of Iowa just throw it away. But don't throw it out the window."
Using your logic, if you plan on driving your vehicle out of your state, you should tint to the lowest common denominator of states you might be passing through. So, if you ever visit New Jersey from New Mexico, you need to rip your window tinting off the front side windows before you go there.
Just as with front license plates and door lettering on cargo vans, the only thing that matters is what they laws are in the state in which your vehicle is registered.
Now, with a
Commercial Motor Vehicle, windshield and side windows are
regulated by the DOT (and are the same as Iowa), at 70% VLT, even if your state allows darker tint on non-CMVs like cars, light trucks and vans.