Caroline believe me I have trained my lab for everyhting else with positive method. But as far as eating from the ground (poo from other dogs, garbage) she didnt want to learn. Many times she used to find food and wouldnt come back if she hasnt finished it! And in this part of Greece where I am from people tend to murder dogs that are homeless by putting all kinds of poison in food..
As far as the try not having it on her point, I was suprised also to see that regardless the collar or not she now continues to behave correctly.