Reminds me of the dropzone antics on days when it was too windy to jump. We'd haul out old Paracommanders (round parachutes), attach the suspension lines to whatever would roll, slide or drag across the grass. Injury rates would go up quickly. It was definitely more dangerous to be there when no one was jumping. Yep, we were drinking..snip
I also found this video taken a while ago, it appears to be Maine Sail after he had a few drinks at lunch, and felt the need to make a demo video on make shift spinnakers, without using his boat...
http://www.youtube.com/watch?v=bhN_A4mr5PI&feature=related
As we saw in the intro they did wire up a way to activate the brake lights and the turn signals, and electric trailer brakes are not uncommon...Or they've got a very efficient and invisible braking system.