I only read the first and last page of this thread, but Ive been to mexico tons of times on surf trips. Ive flown, driven, and bussed it through mexico down to michoacan.
But yeah, its easy to bring some with you. I flew into Guadalajara which is a super huge and busy airport and there wasnt a dog in sight.
Recently in mexico though, small amounts of drugs (like less than 3grams) has been decriminalized. BUT, there are a ton of corrupt cops and federales.
When you are in mexico and traveling around. You can always buy more weed where you are going (especially in tourist citys or remote surf camps).
We decided one day to hit up a point break in Guerrero after staying 2 weeks in Michoacan. Well, we had some dank and well, buds suck in Guerrero, so we took about a quarter. Stuffed it in my shorts under my nuts. Of course leaving michoacan we had to go through a checkpoint. I literally stood next to a Federale, had a conversation with him for about 10 minutes while his buddies searched our truck (loosely) for "guns" all while I had weed under my nuts.
The thing is, mexican cops have this "machoness" to them that they wont feel you up during a search. I also have a friend that lives in Colima (white guy from texas) and he drives into and out of michoacan all the time with weed. His bigass red truck sticks out like a sore thumb too. But if you're cool, speak some spanish its all good cause they're bored as hell standing around with machine guns. LOL Sorry for the long read