I'm sure that the Border Patrol does eventually give water to the people they capture before deportation. However, not everyone runs across las migras, and I see it as an act of basic human compassion to ensure that they don't die a painful death.
So, should we provide lunch meat sandwiches as well? Heck, why not just give them a one way bus ticket to the American city of their choice?
I'm not trying to create a strawman, but I really don't understand what you are getting at here. People can die many imaginable ways crossing a desert. What is your solution?
I am all for having a water station half way across the desert. Heck, advertise the fact that you have this water station. If some illegal immigrants get into a tough pickle, then they have the water station to fall back on. The catch is that you will be taken back. It's your choice.