[yorkiemini]

When Cali was in service dog school for all those months they spent many, many hours and weeks with distraction exercises. (Yes, there were cats!)
When they moved from a leash to off leash work they would take a light weight leash clasp and tie some clear light weight fishing line to it. Then they would start working her by sending her off, but if she would get too friskie she would be surprised by the fishing line leash and it would sometimes catch her up short and it didn't take her long to decide whether she was really off leash or not.

I thought it was rather clever and when I take her someplace that I think may test her I get the fishing line leash out!