> existing somewhere without spending money

Existing without spending money works a lot better when you perceive and comply with social norms. At a mall, you're unlikely to meet loitering enforcement for reading a book in the food court all afternoon while sipping a drink you brought from home. You can meeting your local walking club there too and walk for miles chatting without purchasing anything -- if you're not bowling over the shoppers.

But if you camp out in the entrance of the mall and roughhouse with your highschool buddies, your antisocial behavior will drive away customers. Perhaps you can't perceive this, or perhaps you do perceive it but don't care -- either way, once you're making shoppers uncomfortable, you're a strict liability.

This doesn't mean you can't be kicked out for other reasons. But you get a lot farther if you play to your audience.