If the restaurant advertises all-you-can-EAT condiments then it would be within my rights to stuff myself silly on ketchup. But filling my pockets would be against their terms. Similarly, if they advertised “as many ketchup packets as you can take home for $5”, they can’t cry to me when I bring home their whole supply of ketchup packets.

Similarly, if Dropbox is offering unlimited personal storage, they’d be well within their rights to ban me if I resold it. But using to store 20TB of my own shit is me doing exactly what they advertised.

I wish the world was as utopian as you described. Unfortunately, and I’m sorry to say, that’s an extremely naive world view you hold. I hope you won’t be taken advantage of by people with less good intentions.