As regrettable and infuriating as this is, it wasn’t entirely unforeseeable. There have been many recent reports of Mexican bandits patrolling the Mexican side of the lake looking for Americans to rob. Until this, the victims were fishermen, which makes some sense. You’re more likely to be carrying valuables on a boat as opposed as to when you are on a personal watercraft.
That’s not suggesting it was the victims’ fault. However, nobody who is paying the slightest attention to border violence should think going into Mexican waters was a good idea. I don’t think hikers in Iraq or sportsmen at Falcon Lake should go anywhere near the border.