Invisible Fence(s), are there un-intended consequences to the quality of life of the protected animal?

I should begin with a Disclaimer:
I have never owned an Invisible Fence or an invisible fence-like system. Have always had a dog and when it comes to the safety of my dog, I have always placed the well-being of my dogs (both German Shepherds*) before all other considerations. And I understand the argument that with a product that will prevent a dog from running off and being hurt simply because (their) human had a momentary lapse, or they jumped their fence there are expected to be 'trade-offs' Am neither an animal psychologist or expert in fence systems or Operant Conditioning, for that matter. Writing purely as a 'civilian' who thinks that dogs are perfect lifeforms.

Am writing this Hub simply because a number of families in my neighborhood have gotten invisible fences recently. This is a residential neighbhood in a rural community, the house lots in this area are good sized. a minimum 1/2 acre with many being 2 or more acres. The conventional installation (of these containment fences) is along the perimeter of the properties, including the front lawn. This means that the dogs are able to come within a foot or two of the street.
We enjoy walking around the neighborhood, with our dog. Quiet street, hardly any traffic, nice walk.

The 'problem' or (it might be better to say the 'concern'), I have started to feel is coming from watching the behavior of the 'contained' dogs that we encounter during these morning walks. The dogs see us approach 'their property' and as required by instinct, they will announce their presence by barking and as we continue to approach they (usually) charge the boundary, prepared to defend their territory and their pack. This is as it should be.

But I have noticed that the dogs will charge and as they interact with their Invisible fence system, the tone of their bark changes. (Those of us who love dogs have all learned to recognize the language of barks, the warning bark, the welcoming bark, the 'come-lets-play bark, the who's there bark?, etc.
The change in the tone of the barking that I notice appears to occur only when the dog is getting their negative reinforcement. I admit to ignorance in regards to the conditioning schedule that is required to train a dog refuse to cross (an) invisible line. Maybe this is only with initial conditions, maybe refresher courses are used. Don't know.

But I would swear that with the dogs in my neighborhood, there is something going on with behavior of the dogs when they are engaged defending their territory.
It is almost as if, they must charge, they must defend their territory...that is an instinct.
And even though they may "learn" not to go too near the street, because they know that they will get a shock...when they are being driven by instinct,  they simply must do this. The problem begins with the negative reinforcement becoming associated with the people approaching, the dog is learning that pedestrians equal pain. The Invisible Fence conditioning becomes more and more generalized.

Just thought I would throw that out there.

I normally write hub about personality types and the Wakefield Doctrine (the theory of clarks, scotts and rogers) but today my morning walk got me thinking. (And no telling what trouble follows from that!)

* The photos in most of my other Hubs use photos of my first dog, Ola. She was perfect.