Employees should suggest "decoy day", when everyone bands together to build fake cars to fill the parking-lot and thus impress visiting clients. You could organize a whole Potemkin Village thing, where a small number of in-office employees are re-used to look busy for those visiting clients.

So dumb.

Just do what every company i work for does. everyone comes in the week ppl visit and up the dress code then. When they leave back to baseline sweat pants in office and 2-3 days a week.