Taking your walking into a store analogy, what you are actually doing is taking an xray of every potential customer, going through their pockets, recording every receipt from their wallet and then uniquely tagging them with a barcode all in the very moment that they touch the door handle to enter. And that's assuming you are not trying to be evil.

Could you please disclose the name of your company so I can be sure to avoid it like the plague?

The extent to which visiting amazon.com is like walking into a shop is the extent to which Amazon puts up a facade to make it feel like that. That we're exchanging messages is not just what's happening behind the scenes, it's the essential truth of how communication happens on the net.

If I were visiting your shop, it's totally reasonable for you to check to make sure I'm not stealing anything. But I can't steal anything of yours by sending you messages! (Setting aside the possibility of me hacking your server, but that's not what you're sending me javascript to check on.) Hopefully this expresses more clearly why I don't think the shop analogy holds water.

If "sending messages" is too primitive of an abstraction, we can imagine exchanging letters in the mail, or buying a newspaper, or something like that.

(BTW, I'm sorry for the unconstructive sister comment here - I definitely don't condone it.)