Is it impolite to bust out a phone right in front of a sales rep and say "hold on, let me check amazon", sure. But there's no moral responsibility on the customer's part to do business with anyone because "hey man, it's more expensive for me to run this business".

This isn't some surprise to retail. This has been going on for over a decade. You can't compete with the internet on price for (many) things. But you can compete on immediate availability, customer experience, etc. If you're fighting a price fight with the internet, gtfo of retail.

As I said, it's unethical to use a store as a showroom and then buy elsewhere. It's a simple concept, and I believe you're being intentionally obtuse and disingenuous in your reply.

Yes, this is inconvenient for the people who own those stores. No, the consumer isn't doing anything unethical.

But if people continue to behave the way that you're suggesting is okay, we'll end up with very few brick and mortar options and we'll have to rely entirely on sight-unseen information in our purchasing decisions.