Does anyone know what the procedure is with price matching at a store like Wal-Mart?

I know places like Best Buy had computers scattered all over the place and salespeople could bring up a browser and check the price themselves.

Wal-Mart doesn't have that. Do they trust you bringing up a price on a smartphone and showing them the screen? Do you need to go to the customer service counter and they look it up there? Could you show them a faked screencap/print of an Amazon page and they would trust that as legit?