Not only will KCBS membership get you a day pass, but you do not need a RESTAURANT business, just a business. My dad is a wholesaler of silk flowers, he got a card. I know someone who owns his own HVAC company, he has a card. I know someone who is an electrician and is incorporated, he has a card.
You just need paperwork showing a tax ID # and maybe 1-2 other forms - call ahead and ask as to what is needed, but it does not have to be a restaurant business to get a card.