When I flew to Mexico, they didn't even check our credentials at all. On the plane, they make you fill out this visa form, which Jennie and I did. But we accidentally mixed them up. I had hers and she had mine.
The customs agent in Cancun took her birth certificate and my immigration form and stamped the form. Then I came up and he took Jennie's form and as I was digging in my bag for my birth certificate, he just waved it off as he stamped her form.
I couldn't believe that. I mean sure, I can see that Mexico wouldn't be trying super hard to keep Americans out for any reason, but I thought it was really lax anyway.