I'm just going to chime in here, if I may...
Correcting a working dog when it's young can inhibit it's drive - yes, I've seen it...and I nearly had it happen to Nisha, and may bring about nerve issues. However, there are other methods that one can use to train a dog to do (or not do) certain things. You don't need to use corrections. I taught Sacha not to jump on people by using negative punishment (taking away something good to decrease a behavior).
That's the first thing.
The second thing is that I've heard many trainers tell handlers not to stop their dog from jumping on people. Not because you need the jumping for the sport, however. More because you don't want to correct the dog. This tends to be an error on the part of many trainers.
PERSONALLY, I allow my working dogs to jump on me. I NEVER stop them from doing so (which is one reason why I haven't been interacting with Nemo b/c he launches when he jumps, and we're just afraid he'll push me backwards which my knee isn't stable enough for, yet...however, I can do the drug stuff with him b/c once he has the kong - which is his reward - he jumps on me gently)...but, I digress...I allow my dogs to jump on me. In Nisha's and Cy's case, they jump on me after they've been given the tug reward...and they do it more for lovin while they have the tug in their mouth....kinda like "look what I got."
Because I allow my dogs to jump on me, and Greg allows them to jump on him, and many of my working dog friends allow my dogs to jump on them....I can't possibly expect my dogs to differentiate when they meet someone who may not want the dog to jump (the good news is, I don't have to worry about Cy b/c he typically doesn't have a desire to jump on random people)...so, out of courtesy, I don't take my dogs out to meet random people...and if I do stop to speak to someone, I put my dogs in obedience mode...either sit or down...but the command, and the correction if they break, comes from me.
As far as corrections go - aside from Greg and I - I don't want random people correcting my dogs. Personal preference. I have allowed decoys to correct my dogs...and I've done that to get certain behaviors from them while I remain at a distance (this is especially important with Cy b/c if he thinks the correction comes from me, he's so sensitive that he comes to my side
I guess my overall point is this: if you want your dog to act a certain way that may not be acceptable to other people, then don't take the dog around those people. And, if someone is repeatedly doing something to your dog that you don't like, well...guess what? You have two feet. Walk away...WITH YOUR DOG!!!! You don't have to continue to ask the person not to do it....especially if you feel like it will hurt your dog.
I was once working with a new decoy who esquived Cy...and he broke his tooth during the esquive. When I brought Nisha out, I asked him not to do that to her as she was still young and I didn't want to screw anything up in her targeting, and I ESPECIALLY didn't want her to break a tooth. The first send, he esquived her. Guess what? I grabbed her leash, and put her away. You don't have to allow something to happen to your dog that you think might screw it up NO MATTER WHAT you are training it do!
Okay...I'm done...and I apologize if my post made no sense...