Yeah, that's probably true. Besides that, I don't think you can just avoid a whole lawsuit by slipping over the border. It's maybe a bit of a romance fantasy, maybe echoing the western trope of someone being pursued by the police and making it across the county line or more significantly across the Rio grande. I find it hard to imagine that back in the wild West, at sheriff posse or military contingent would simply let you go because you crossed the border. Much more likely they would hunt you down, string you up, and return your body and say they caught you just shy of the border. But it makes for a good movie scene