Interesting one, i can safely say i dont think i have a chance of calling mine off once there running, BUT i think it could be a very handy as sometimes things crop up in the field, i have never tried it with a lurcher but i think i could drum it into them, but i wont. My manwork dogs were very very high drive and could be called off a bite 9 times out of 10 but this was often required in competition and they only way to acheive it with many of them was using an electric collar. As i said, i believe it can be done but requires a lot of hard work and its not something i will insist on........