I've encountered similar instances. And, fortunately, I've experienced the exact opposite.
In a similar experience, I was auditioning a pair of PSB's as well as JMLab's since the dealer sold both. As I was about to walk out (since I had only just begun looking), the dealer stopped me and chatted me up. Wanted to know what I listened to. I explained. He told me I'd probably be better of with the PSB's. Seemed like a fair and honest suggestion. Then he asked what I was currently using. I told him B&W's. What followed was a verbal barrage about how B&W is way overrated and how he can't understand how anyone can listen to them, etc etc. Now, I don't know how good a sales technique this is...belittling a customer and making them feel like the item they purchased with their hard earned money was a mistake. I'm gonna hope that approach doesn't work very often. Also, after tearing me and my speakers a new one, he then asked what else I was considering. At the time, I was also considering internet direct. I tossed out the name Axiom. Oh boy. That got him going. I haven't been back to that store since.
On the flip side to that, I have a local dealer, whom I purchased my speakers from, basically talk me OUT of a sale. I was looking at subs and, paraphrasing of course, he essentially told me, "yeah, if I were you and had your budget, I'd consider something else...i think you can get a lot more bang for your buck if you shop around." Now that's what I call an honest salesman. It worked though. I keep going back to them, even if it's just to browse. And, odds are, if I do intend to buy something anytime soon, my money will probably be going to them.