Oh man, I guess that explains how all the people who go to Russia each year speaking English as their first language (because humans don't have the ability to learn more than one language, which I forgot... my bad) to purchase illegal goods just somehow disappear without returning or anything. And oh right, I forgot literally no one in Russia speaks English, which is the language of business/commerce/diplomacy throughout the world. And don't even get me started on how literally everyone in the world is a massive idiot and will go to a foreign country with the intent on getting their kids back without taking some kind of precaution to make sure they aren't shanked. And oh yeah, the "black market" is literally just like it is in the movies, some shitty alley in some crappy neighborhood where all potential customers are killed for money (rather than letting them buy what they want so they come back later... seems like something you would want to do when running a business, even an illegal one).

And I forgot the internet doesn't exist, nor all the huge number of "deep web" blackmarkets (or even blackmarkets on the open web). And lets forget about smartphones because those things can't be used for anything useful.

I mean, do you really think everyone in this world is as stupid as you are? Do you think people are incapable of stringing together some thoughts and coming up with a plan? That they can't research on the internet? That shit exactly like OP just described doesn't happen all the time? What about the guy who did exactly what you're saying is impossible? He went to a deep and unsavory part of Mexico and got his kid back from his ex-wife who took him? I suppose that didn't happen. Sure, it might be a bit harder to pull off in Moscow and he MIGHT get killed, but he isn't concerned with dying in that situation, is he?