Stealing from the Poor

Imagine two people, A and B. B sells various products. A buys one and gives it back to B. B resells it to another individual. It seems like A should be able to do this, it's just a donation.

Scenario two: B sells A a product, but never gives it to A. B has stolen from A.

Scenario three, a combination: B sells A a product, and never gives it to A. Instead B gives it to another person, C. Now let's say C just gives it back to B. It seems like C is just as responsible for the theft as B is.

I just bought some pretzels from a vending machine. It also dropped two bags of sour cream and onion potato chips, which I don't care for, that were dangling nearby (already paid for). I gave one bag to some people working nearby, but the other I put on a shelf with some similar chips, behind a chain window protecting some food products for the night. There are cameras that watch this spot for theft, but what about this kind of theft?