http://www.reforma.com/ This link, a major Mexican Newspaper has 2 pictures showing the human chain. As you can see numbers are dwindling.
I couldn't tell from Reforma's numerous photos that the numbers are dwindling. The distance between the Zocalo and that other place (Torre PeMex maybe) is substantial, isn't it? Maybe the use of a human chain wasn't necessarily to hide numbers. I guess the human chain has symbolic usefulness in that it shows how many roadways can be blocked with this enduring culture of impunity. And it's a fresh new approach to AMLO's frustrations.