I guess there is a benefit to the whole leash tug-thing

This is really funny video. Watch it all the way to the end. Although that lead out is pretty darn big!

I don't think I would be comfortable competing in a non-secure (fenced) ring. Luckily all our local outdoor trials at least have snow fencing and some have chain link. It looks like this one just had poles with tape, like crime scene tape. :-) I think that's the way they do it in the UK too.
I surprised stuff like this doesn't happen more often.