If it's tied down properly then there would be no worries.

I loaned a guy one of my tiedowns when his car slid off the back of his trailer. He was using a small old chain and it broke, car was in neutral. He mailed it back to me later. He was going to the road race and I was going to the autocross. Didn't know him. Saw him on the side of the road with the car half off the trailer and stopped to help him.