I think it would have to do more with governments than exit. There were many reports of N shipments getting confiscated, probably at customs. There were other reports of N getting delivered and, shortly afterward, the recipient getting knocks on their door from law enforcement. I think the government got wise, since there were a lot of N deaths. It wouldn't have been that hard for them to figure out where it was coming from, since it was talked about way too freely on this, and possibly, other forums. All it take would be someone from law enforcement to infiltrate on SS, find out the information as to how to order it, and have customs seize it. Then they could backtrack where it came from and work with the Mexican government to shut the operation down. The US has quite a bit of power, and if there is something they want, they can strong-arm countries, in this case Mexico, to go along with them, because there are plenty of things that Mexico needs, and gets, from the US. If the email accounts were shutdown, it wouldn't have taken much for someone else to step in and claim the addresses for themselves and start their scam operation. And as we know, or should know, Western governments share all kinds of information, so I'm sure whatever the US learned of the operation was shared with many other countries.