If it's a service dog, you've got no beef. If he's pretending, you'll have a hard time proving anything, but he'd be really inconsiderate if he did that anyway. I do agree dogs should not otherwise be allowed into shopping spaces. I've been to Prime Outlets (now called Premium Outlets for some unknown reasons since nothing changed to make them any better)...but they wander all over with their dogs on very long leashes and I've more than once seen them use the bushes to do their business. Dogs don't have wallets, and should not be out shopping.