Wow, we got lucky over here i guess. I dont know any body that ties anything down. I do not see people stack equipment as much as i have seen on here though either. Most people just have small sides on thier trailers. I have had mowers bounce up before (unseen potholes and surprise train track bumps) but nothing too serious to worry about. Plus, if someone else hits my i just call my insurance guy. I have coverage on my truck, trailer, and equipment.