Serious question: is it kidnapping if US Marshals go into Mexico and grab a fugitive to bring him back to the US? Maybe it is, maybe we (generally, as a country) are okay with it under certain circumstances or for certain offenses.
I have no idea, I just know it has happened in the past both with and without approval/consent of Mexican officials. I don't think they'd be super public about it either way. Either it happens very rarely and that's a safe way to evade capture, or it happens every day and people will stop running to Mexico.
