I photographed a NADAC trial and they have Gamblers as a class. They put down some of the safety tape (i.e. "Caution") and you direct the dog without crossing the line. This field had a lot of Goose manure on it because of all the Geese that winter there. I went out and bought tape that said "Bio-Hazard" and put it down in place of the "Caution". Everybody enjoyed the joke.