Look at the above picture. This man is transporting a cart in a dangerous way. If you are passing by him on your bike or in your car, an accident can happen with a small mistake by this man. That accident can kill you or other people around.
So this man is committing a crime by endangering our lives. He probably should be arrested and jailed.
This man is doing this because he wants to provide us cheapest possible service, not willingly but in a desperate attempt to feed his family. We, the people with money, have the power and leverage to negotiate hard with poor people like him. We often think, so naively, that if someone has agreed to provide a service at a certain low price then it means that he can and he is making a good profit on it.
Probably wrong. Poor people have poor negotiation skills and little or no options. So they grab whatever they are able to get right now.
This is what is called externalizing the cost. These poor people are bearing the cost of providing us the cheapest possible services and helping us enjoy our life with all sort of luxuries while suffering themselves at the same time.
I would suggest to think twice when negatiating really hard with poor people. I would also suggest to go even further and, whenever possible, pay a little more than what market is paying. This is going to save you or me from a big disaster someday.