Could have done it the legal way.
Less gassy.
The BEST approach would have been to have remained in the south in Mexico and have contacted one of our embassies there. Crossing all of Mexico before even applying is presumptuous of them and right there send up flags for the sorts of folks involved.
I'm thinking that the vast majority of these invaders would have been rejected if they had applied in their home countries.
And they knew this.
That's why they chose the short-cut method.