Employer told me I have to leave my phone in the car tomorrow, is this enforceable?

Mind you, this is the CEO of the company (micromanagement at its finest). I'm wondering if this type of action is enforceable for an individual employee or if it would need to be a company wide policy, and what you guys think I should do in this situation. At the very least, putting a deck of cards in my pocket that resembles a phone to see the look on his face.