Oh boy.. This is a hot button topic!
The remote training collar is not a punishment if used properly. It is a "reminder" send by the hand of god (not the trainer, in the eyes of the dog)... I have put one on to feel the level of signal which my dog responds to and it is not pain, it is like getting a "spark" after scuffing along a rung in socked feet.. it startles you out of your activity.. enough to realize that your
boss (owner) is calling you or asking you to perform a command which you (the dog) ALREADY KNOW.
I took a 12 week course with my dog to learn how to use it. The trainer could see he was training ME more than my dog - who had excellent foundational skills (knew commands) already from a year of lure training.
It took three signals to stop my dog from eating poop. Properly timed, properly volumed (strength not too high). He doesn't look at it any more - nor sneak it, nor eat it. Period.
That is an example of behavior modification.
Using the collar for training requires CAREFUL planning. First lure the dog to complete the command. I often use a clicker during this phase. About 30 times of perfect completion - no matter how boring (and not all at once necessarily)... then phase in the command word(s)... get another 30 successes... Then, unless distractions increase, say the command (and here the schools separate) once then signal from the collar and repeat the command. Some schools say - send a signal with the first command else you are teaching your dog to wait for it... the first school feels you will not send a signal unless necessary.. the second feels you are upping the speed of response time on the command an increasing the likelihood of compliance every time...
BTW - when distractions increase, training -not necessarily "volume" (signal strength) needs to flex back a step or two...
After 3 months of wearing the collar every waking moment (not only when we go to the park), my dog no longer needs it on unless we are going to a new place or there are going to be LOTS of distractions at a place he knows... Then it's on just in case. He has rarely needed a reminder... he no longer has "park bark" and he comes when called EVERY time.
My battery has NEVER failed, the collar has NEVER not signaled (I always have it turned on, and on him properly).
For the dog I use it on, it has made the world make sense. The world now works for him... he knows he is safe and he knows he does not have to pre-empt any other dogs (I do not allow that behavior), and he knows that in a down next to me, NOTHING will happen to him - no signal, no dog attack (I would put myself between him and anyone).
BTW - his weaves sped up considerably when I began signaling (low volume) ON all commands: he has made the "transition" to "I (As the dog) can stop the signal by complying quickly."