Warrant or no warrant, a private property owner is free to prohibit anything from his property, guns included. A private property owner is also free to require a search of every vehicle that enters his property. Of course, you would be free to say no, but the property owner could then prohibit you from entering the property.
I would never work for a company that did this, of course, and I assume most here would not either, but that’s the whole point of a free market - it’s our decision, not the government’s.
If a private property owner is free to prohibit anything from his property, guns included, than said property owner should be free to allow anything of his property, including smoking. Unfortunately, this is not the case. I guess that means the government can tell you what you have to allow on your property.
They’d have to fire me for refusing to allow them to search it. Record and document it all and let the courts take it from there. They’re looking for “voluntary compliance”. I wouldn’t give it to them is all.