I was told that one No More Deaths member, the first to get cited for this "littering", had come upon the body of a girl who had died migrating. Imagine how he must have felt when an officer was ticketing him the next day for trying to prevent the same sort of death for someone else.
No More Deaths members have not only seen the bodies, but they've also seen water jugs slashed and water stations otherwise destroyed by anti-immigrant folks (who else would do it?), who obviously don't care too much about litter.
However, No More Deaths members do care about litter.
Staton said that whenever volunteers take water into the desert they also bring empty trash bags. Along the way they pick up empty bottles, food wrappers and containers, clothes, backpacks and other items left behind by crossers.
In the end, the volunteers probably take out more trash than they are accused of taking in. (Source).
The water drop locations are checked at least once per week to pick up empty jugs and replace the used jugs...No More Deaths believes that US immigration policy based on deterrence is the main source of environmental damage along the border. The policy intentionally pushes migrants into remote, dangerous and environmentally sensitive areas of desert. The response to this trend has been the construction of the wall and the deployment of thousands of Border Patrol agents using 4-wheel-drive trucks, ATVs, helicopters and other vehicles, which destroy the land and disrupt wildlife movement in areas like Buenos Aires. (Source).
One article claimed that the arrests were made because NMD "has been unresponsive". However, according to one of No More Deaths's press releases,
A letter signed by more than 70 human rights, environmental and faith-based organizations and individuals was hand delivered to refuge manager, Mike Hawkes, on June 16 asking for a meeting by July 1. A copy of the letter was also hand-delivered to Secretary of the Interior, Ken Salazar. Mr. Hawkes responded on Friday, June 26 requesting a proposed agenda and list of participants, but no further correspondence has been received. (Source).
You might be interested to see comments from the types of people who think it's okay for people to die crossing the border, such as this:
This type of behavior is not only destroying our national parks, it's destroying America. When are you people going to wake up and realize that these people are breaking the law?! If we break the law we get punished. These people purposely break the laws and then demand that we take care of them and give them the same rights and respect as us legal US Citizens. Give me a break. It's not about hate or discrimination, it's about the law and what the illegal trespassers are doing and the people who leave out water and food encouraging this behavior is called breaking the law and they all should be punished for it. REPORT TO DEPORT!!! (Source).