Some other options to consider.
As posted above try to leave a way out of what ever type of barrier you use. The controlling types in our club wanted a true 3-foot high plastic fence box all the way around each pilot station. When someone pointed out that it would be dificult to get out of if a plane was coming at you they didn't feel that would ever happen. Then the biggest controller of the crowd had knee surgery and all of a sudden an open side was a good idea. From four individual boxes the protection evolved into one long fence infront of the four pilot stations. There is a second shorter fence that protects the inner two pilot stations from possible run-aways in the pitts. But in ten years that has never actually been needed to catch a plane coming the wrong way. Our club fence is only meant to stop an errant landing plane. It is made of landscaping logs and tennis netting . It has stopped 20 pound quarter scale birds from hitting the pilot stations.
Also our runway is 250 feet long. One other policy that helps is to start your takeoff roll at mid runway. That way when the airplane is up to any considerable speed it is already passed the last pilot station and no longer a threat to the other pilots. Image of the field may be found here:
http://maps.google.com/maps?hl=en&tab=wl
or Lat Lon search at 35.54865, -97.589608