Your right anything can happen but any large attack on US grounds or equally blowing up a plane on either side of the border is going to bring the full weight of the US on the cartels. It makes little sense. Cartels have for decades ingrained that into their organizations no matter how violent that may be.
It's a much bigger problem that you all realize. Right now they have authorized attacks on border patrol agents...
I'm not saying that the US wouldn't retaliate, I'm saying our enemies are getting bolder under this administration's pressure. Turns out the closure was because of drones... But it's still a real issue in Mexico that Mexico would love the eradicate.