Perhaps, but I rather doubt it. There are better explanations than it being an official policy of the Mexican government. For example, it's easy to imagine poorly-paid Mexican soldiers being bought off by a very wealthy drug or people smuggler.
I had good info that there *used to be* evidence of Russian military excursions on Alaskan shores.
Sure ... in the context of the Cold War. We're not in a cold war with Mexico, though. The illegal immigration problem is a result of other factors, primarily domestic, on both sides of the border.
Is there any reason to believe that the Mexican government isn't bought and paid for by drug cartels?
Allowing for that possibility, then having the Mexican military running operations across the border doesn't sound outrageous.