This issue seems to be still an on going problem! Frankly it's quite scary if I do say so!
Here is my point of view:
Even though I train my own dogs using a different method with some of the schools as they teach the traditional method. (negative punishment) I use OC with positive re-enforcement! However no matter as to which method is taught, these shocks could make ones service animal shut down totally due to stress, refuse to work the area, bolt causing injury to both of them, etc. They could think that it’s a negative punishment and therefore wouldn’t proceed even if you try to say forward.
I know people say that oh a little shock wouldn’t hurt them. Well unless they have had that type of shock and are in the minds of the dogs they cannot actually state that as facts just an opinion. I have been shocked though didn’t kill me but dang it it hurt! Numbness and tingling isn’t a normal thing for either a human or a animal!
As far as lasting results goes if a dog becomes stressed out over that area then they are not doing their job correctly. In other words if they refuse walking the area and that’s the only suppose to be a safe place for their partner then what happens. Therefore then we have to reshape their behaviour if possible back to where everything is OK. Sometimes it’s impossible and henceforth our dogs would have to retire prematurely, all due to a situation that wasn’t the dogs fault nor their partner.
So maybe the hurt factour may not be extremely high as in a physical factour (though one cannot say foresure), but in a more of a stressful factour this issue hurts both the trained dog and the person with the disability. The training is intense and it’s not an overnight type of thing it takes several years and these dogs goes through many temperament evaluations to make sure they have the right temperament. Then bang being shocked that isn’t normal for them to feel such a thing. Majour issue even if they want to down play it! I feel if only 1 out of 5 has to retire because of safety issues then that is one too many!