OK, in April I had to report that I was on a cattle ranch/rode a horse when returning to the United States from Bolivia. I arrived at MIA. There, they directed me into a line where they do more screening of the incoming bags/travelers who have been on ranches. Some people have told me that they had their shoes taken away and cleaned, but I had already cleaned mine before packing them, and I wore flip flops in the customs line. They must have looked pretty good because they did not select me to put my shoes in the cleaning fluid. So, all in all, it was pretty painless.
I would say honesty is the best policy, it really wasn't any trouble.
If you want a giggle, you can go to the page of my diary listed below and see me on my horsey.
http://peachfront.diaryland.com/photosbolm.html