If the dog ever brakes through to the other side of that invisible boundry.. Thinking of getting excited with seeing another dog, a cat a rabbit, anything that triggers him to ignore the so called correctional electroshock.. And he runs of anyway, than if after all the excitement is over and he desides to go home again.. I guess the boundry works the same other way around.. He will get corrected/punnished with trying to get back home. It will result in a very frustrated dog if that ever happens.
A good old leash is still the best prevention.. 🙂
Personaly i do not believe in such gadgets to invissibly correct the pet with electro shocks.. It's just unatural.. A dog needs an physical alfa figur interacting and correcting it, not a ghost. As Alto says it still requires a lot of personal training and attention, so you can learn the dog to turn back the moment he hears the tone. If you do it "correctly" and are a good alfa, you wont need to metals pins, than the tone will be enough.
But some people just think differently.. Like my girlfriend did, her dog barked when she was out of the hous.. The neighbours complained and she bought an Anti Bark Collar.. So everytime the dog makes a certain movement with it's neck it got zapped by a ghost.. It seems the complaining stopped, so it must work in the users opinion. But have no control over ti if the dog also gets zapped without barking with making the same neck movement without barking.
But still just think of it, why??? Why do you want a dog and leave it alone where it can't be a dog and zap it if it is? Sorry, you should think first, should i realy get a dog in an situation like that? What's in it for the dog? 🙂