Sue, that is worth a thought. I have not done that kind of training with Ceilidh, she stands nicly when I talk to someone but if she is off the lead or if I do not talk to someone she pays no attention to them and if they pay attention to her she does jump back and bark which is not the best either but she would never go for anyone, just barks because she is scared of some people.
The idea of vet surgerys having a scanner on their doors is great but then that will only get some dogs. Like you say so many are not taken to a vet surgery.