OP makes a great point. I had the same experience about 5 years ago here in Scottsdale with US Tube Audio. They advertised here all of the brands that they carry and it sounded great. On a day off, I spent an hour driving there to check them out, only to find a professionally printed sign on the door (apparently used frequently) saying that they were out on an installation!
I have two problems with that. First, there should always be someone minding the store during business hours. Second, if you are going out on installations during business hours, you should advertise "by appointment only", which they didn't.
To make matters worse, when I politely called them on it, they got nasty and threatened to report me to Audiogon.