Walking Into A Brick & Mortar High End Audio Store

I think it depends on your expectations. If you just show up at a store and expect to demo a particular combo of gear that isn't already set up, you aren't likely to get the time and attention that you need. For starters, the owner or salesperson may already be busy with another customer.
If you are just browsing, fine, but I've still found that, unless the dealer knows you, you are better off making contact and arrangements first. Obviously, one can do whatever makes them happy, but if people complain about not being treated 'right' at a dealer's, they should consider how to approach the process in a way that will maximize service and minimize attitude. At least that's been my experience over many years, dealing with a variety of so-called 'high-end' products, in audio and other things. And, I've ruled out some dealers simply based on my experience in talking to them over the phone.

I think that approach makes a lot of sense, Whart, and is respectful both of the dealer's time and your own.

IMO Mapman and Bcgator have unveiled the issue central to this B&M discussion. I believe that genuine and real customer service is a lost art. Typically what we experience today is only lip service. This lip service is ultimately just another marketing tactic to drive sales. It isn't service at all. Consumers know this. So, now that customer service has been effectively removed from the equation, what do we have left? Product performance and price! We live in an age of disposable commodities (which impacts the product performance), and I believe this is partially a result of this lip service. This is why the sub set of price sensitive consumers is so substantial now. We have a generation (perhaps two now) of consumers who know nothing of true customer service. Nevertheless, I firmly believe that consumers who experience true customer service find it attractive and will be willing to pay for it. I think this is true in all aspect of the market as well.

Absolutely!

you would want to stay current so when the up-grade bug visits, you will be ready. Also, some companies offer new gear every year, it is good to see and hear the updates.
Keep us posted.

To explixitely answer the OP's question, yes, it's absolutely cool to walk into any store that holds itself open for business