You and I come from the same think tank it would seem. My son was a narc along the border and once spent six months underground on a special mission for the feds. The results of his effort were fabulous. He fingered an entire group of people who were involved but had never been suspected, one case amounting to over a milion dollars and drugs and cash being intercepted near El Paso.
But the story didn't have such a happy ending for my son who was fingered by someone in his own department and was posted in the drug world as a trophy they would pay 100,000 dollars to the man who killed him.
He was forced to flee the area and spent several years in another locality, having foregone his career because of his families fright.
He has told me many tales about what goes on along the US/Mex border on a routine basis and when you hear it from his side of the dispute you just have to wonder why anyone would risk their lives in such an iffy profession.
This is a common covert practice to get the bad guy. Has been for many decades. In order to do covert work in the criminal world you work with criminals. So I would tell those parents to be the change they want to see. As a parent I would weigh the loss of lives for doing nothing versus doing something and then I would seriously look at why things went wrong and take myself to Washington if I felt my child died for nothing. I would tell them how much is too much is their's alone to determine.
What I think this also shows is that border guards are as brave as any law enforcement officer and it has always been a dangerous job but it is even worse now with drug running and every element of crime. My sympathies go to these parents.