B-O-O-K-S spells "Public Toilet"

Yesterday an older couple (husband & wife, presumably) came into the Institute and, shortly, the wife approached the counter to ask politely if we had a restroom.

pictured: ambiguity

We responded-- politely-- that we're afraid we don't have a public restroom, but directed her to one close by.  We overheard her tell her husband, "They don't have a restroom here, we need to go next door."

But her husband was on to us.  He knew the problem.  She just hadn't asked penisfully enough.

"Where is your restroom?" he bellowed at us.

Despite the misleading sign immediately next to the front door at eye-level stating that we have no restroom, we do not, in fact, have a public restroom.  We reiterated this to him.

"I'M NOT THE PUBLIC, I'M A CUSTOMER."

This is a common sentiment amongst our visitors at NIOLIT: 
I am NOT the public.  How dare you imply that I'm merely part of the vulgar horde? 

I am always tempted to inquire in return: When you buy a ticket to the opera [as I'm sure you frequently do], do you go bursting into the dressing rooms while insisting you're not the public?

I blame the major book chains, which inevitably feature some chain coffee-shop (Starbucks, Peet's, &c) in miniature.  According to state law, all establishments which serve food or drink must provide customers with a restroom.  Customers who are used to frequenting the chain stores, then, associate book shops (and their coffee corners) with toilets.  

"What kind of coffee do you do?"

We do not vend coffee.  We are under no obligation to provide you with a facility for excreting.  You'll just have to pee-pee before you leave the house like a big boy next time.