Hmmm...interesting take. It seems to me that, if an employee consented to the search as part of the terms of employment, then no deprivation is occurring.
I also wonder about applying the interstate commerce clause to this issue, but that's simply because I think it's abused in many circumstances. Perhaps that's for another thread.
That said, I'm open to persuasion WRT the 14th. I think I understand it in general terms, but perhaps I'm missing something. Can you provide a link to a good source?
In this case the concerns of the employer are not the workplace and workplace safety, because the guns are locked in the car, out of the sphere of the workplace, and the employer(s) deliberately linked them with, employee mental stability and illegal drugs.
I understood the policy to be in part because guns in a locked car are readily retrievable and can be brought back into the building. So in that respect it may be about employee safety (or at least couched that way). As to this company's true underlying motivations, you may be right.
My suspicion is that this is motivated by lawyers afraid of a lawsuit.
The economic concern makes it an extortion of employee rights per 18USC241.
" I understood the policy to be in part because guns in a locked car are readily retrievable "
They're just as retrievable as any kept at home, or in vehicles parked outside the gate. Criminals have already demonstrated that. Normal folks(gun owners) have already demonstated beyond a reasonable doubt, that they don't consider shooting folks at work valid, and don't do it either.
Employers are not responsible for the criminal acts of their employees. Seems they have plenty of money to pursue court battles and propaganda campaigns that amount to a back door gun grab.