This is a story I heard recently.
It's a lovely sunny day so you and a group of friends decide to go for a picnic down by the river. You get out the blankets and the food, everyone's having fun, when suddenly one of the group spots someone coming down the river. They seem to be struggling and they're being swept along by the strong current. You know that not much further on the river goes over a waterfall; it would be impossible to survive. It is imperative that you act. Holding on to each other you stretch out into the river and catch the person as they come by. You drag them up onto the bank and rap a blanket around them. Everyone's congratulating each other and very thankful that you managed to save the person.
Just as you're sitting back down though, you spot five people coming down the river, splashing and fighting to stay afloat. There's no time to think. You jump into the water and try to catch as many as possible. Everyone is involved in pulling the people out of the water, but when everyone is back on the bank you only count four rescued people and you realise with heartbreak that two people slipped by.
Then someone shouts that there are ten people coming. You're all feeling out of breath, but everyone jumps in again. Five more people are rescued, but five others aren't. By now you're tired, the sun has gone in and the wind is picking up. You're thinking of heading home, when twenty people appear in the river. Everyone musters themselves and you go again, this time rescuing ten people, but losing another ten. You don't know whether to rejoice for the rescued ones or mourn those who have gone.
It occurs to you that this doesn't seem to be stopping and as valiant as your rescue efforts are, at some point someone has to go upstream and find out who is throwing these people into the river in the first place.
This story was used as an analogy of human trafficking. All the time there are people being rescued from horrific situations, but the number of people in slavery around the world continues to grow.