Ah, I would say that is worse than piracy, since you deprive them of the ground for a time.
Maybe, in my mind I was picturing a situation where someone had lots of property and didn’t realize that anything had happened. I see your point though, that in theory you’re depriving them of the use of it whereas with copyright infringement there isn’t even a second where they can’t enjoy their own property. They only potentially lose out on a sale.
Sneaking into a concert that isn’t full is probably a better analogy. You get the experience of the concert without paying for it, and the venue owner maybe loses out on a sale without knowing it.