> It's definitely anti-competitive in spirit

Where do you draw the line with that? What if you were in a store, saw a product, and then asked the clerk 'can I use your phone I want to check the price at one of your competitors?'. Is that any different? Even if the phone line doesn't cost anything per call (it's a fixed cost let's say).

Competition, honest competition, doesn't require you to make it easy for customers to see if your pricing is fair or high or whatever. Mostly if stores don't enforce this (even with taking of pictures) it's because from a practical standpoint they can't enforce it or get employees to battle customers. Not because they don't have a right to do so.