I've only been down to Micos twice, but Grant and Polo were awesome to us. Grant hooked us up both times when he didn't have to. I did go out of my way to be respectful and easy to get along with, but it worked out for me.
Don't know why Grant has had run-ins with past kayakers. This is the first incident I have heard on Polo.
Goshorn would be good to hook up with if he goes down this year. He's superorganized prepping a trip and we both can make it around Mexico knowing less than 50 words of spanish.