As far as shock collars go, I wish they'd put them on the person(s) that invented them!! I think of it as cruel & unusual punishment! Grrrrrrrrrrr!
Any piece of training equipment can be misused, e.g. you can inflict damage to the neck of a dog with a "gentle leader", dogs can be severely damaged by flexy leads (as can people!), etc. "Shock" collars are badly named. Used at a low setting, they give no more than a mild tingle. And yes, I know that from using it on myself. Abused is another story. But not recommended for a pup, and certainly not recommended for a handler who has not been thoroughly trained in their use. Yes, I have used one, to keep my Basenji safe while letting him enjoy the freedom of being off leash. He was always happy when I brought out his e-collar, because it indicated an off leash walk, which he enjoyed. Most often if I used it at all it was for "leave it", and his reaction to a light reminder was a look that said "oh, alright, if you insist". No yelps, no drama, just a happy dog enjoying his freedom. I will shut up now and wait for incoming!