Store auditioning and then buying on-line from others. How do you feel about it ?

It erodes your soul but who cares, right?

I guess you can do it once at a given dealer but don't expect them to keep welcoming you back. In my experience treating dealers fairly serves you much better in the long run -- doesn't mean you have to spend all your $$ in once place but at least give them something for their time

Exactly. I would offer to pay for their time, I think a fair rate could easily be negotiated.

I think it's ok, sometimes....

The auditioning wasn't done with the undisclosed intent to buy somewhere else. If price was the issue, gave the LAS an opportunity to come close in price.  "Hey man, thanks for taking the time with me the other day.  I'm about ready to pull the trigger, but I did see X-super-cool-device at Y authorized dealer, online, at Z price.  Can you sell for that?"

Or later found a pre-loved item at a significant discount.

Or the buyer does buy a reasonable amount of stuff from the LAS and otherwise has a good, ongoing relationship, including referrals.  But, then, wouldn't the buyer probably be able to negotiate a deal close to the online competitor?

Or got a package deal that includes "necessary" stuff the LAS doesn't carry.

Or the LAS folks were jerks.  Yes, they exist.

Loathsome to go audition something already seen online, have the LAS give you its best advice, spend all day trying stuff out or even allowing a home audition, and buy somewhere else to save a few bucks, especially without giving the LAS a shot at coming close in price---double especially if the LAS is cool about questions and service concerns.

Mea Culpa, 
I heard the Ayre Codex at AudioConnection and bought a used unit here on Agon. I felt bad that I didn't give him a chance to sell me one.
In fact I bought all my equipment used- a lot of it from Johnny's customers. I couldn't afford it otherwise.
I try to buy what I can from him, like cables and accessories, but the big ticket items.... Oh well, you know. 
As a small business owner, I know how hard it is to make a living. Though I do try to steer as much business his way, as possible, through my posts.
For his part, John Rutan has been nothing but generous in dispensing advice and information. When I win the lottery, guess who I am going to buy from?
Bob