ORIGINAL: Tom Nied
I use a loop of parachute cord (any good strong cord should work), that on one end I have created a small loop that I can put a long screwdrive into the ground to hold it and with the rest I loop over my vertical fin and horizontal stabilizer. Take up the slack I've never had a plane get loose on me.
As a safety officer I have no problem with this method. But I have cut off roten ropes and pitched 'em on occasion.
Don't tie off to the tail wheel though. We had this done at our field once with the guy in front of the plane wide open (wrong in SO many ways). It made the oddest noise when it hit him in the stomach. Minor abraisions and bruises, he was VERY lucky.