Wow, the cross your straps opinion was one that I got from the trailer rental guy and just about every place I searched on the internet. Many on the internet not only cross their rears but also their fronts as well. After reading your post I guess the determining factor is where the tie down points are on the trailer as compared to the attachment points on the car. If they are slightly outboard you already have your lateral hold built in. If for some reason they were at the same width you might get some side to side movement. I am off to pick up the trailer within the hour. Hopefully it will all become clear when I go to strap down the car.
Jeff
Jeff