As soon as the insurance company and the legal department catch wind of this, anyone that files the necessary notification will be on borrowed time.
Remember...Texas is an "at will" employment state. They don't need to give a reason to show you the door. IANAL but, it might be hard to prove a violation of this law on the employers part.
One other aspect of this law that I don't care for is the fact that providing intent of storing a firearm in your vehicle to your employer would also be providing a gun shopping list to a thief if that list or database were to fall into the wrong hands.
I think I'll stay with the current unofficial "don't ask, don't tell" policy that seems to work at my place of employment.