Yes, courtesy should be reciprocal. But in this particular instance it must begin, as it should with any service industry, with a smile and a rolling out of the welcome mat from those offering the service. Hopefully, the would be customer responds in like fashion.
I'm amazed at some of your comments. It suggests itself to me that some of you don't know how the real world should operate. Either that or, you've led very sheltered lives.
I've never wrote that the customer is always right. What I wrote was, that the customer 'was king'. Big difference.