[picardythird]

> A store can have a policy like "limit 1 per customer" but that doesn't prevent me from getting 100 of my friends from buying the thing.

Sure, and if there's urban chaos, there's nothing preventing me from looting a store. Or sneaking stuff in my backpack. It's still stealing.

As to your example about the art, it's more like if one piece of art is in the window, but the rest of the gallery you can only see if you buy the ticket. But there's a door in the alley you can sneak in to and nobody will notice. So you sneak in the back, avoid paying the price, and get to see the whole thing for free. That doesn't sit right with me ethically.