
Just wanted to add my 2p for this one.
I would NEVER recommend electric fencing for any type of dog, regardless of the reasoning - there are too many potential downsides. The risk of the dog running through then not coming back because of the shock is one, and of course stray dogs can come through no problem.
But it's the behavioural issues that are the big ones for me - I have read so, so many stories of severe behavioural issues resulting from these fences that it's just not funny. To name a couple;
A schnauzer that barked at passers by. He would run at the fence and get shocked, and associated the shock with the passers-by. He eventually got so aggressive because he thought they were causing him pain that he ran through the shock and attacked a dog. He may have actually killed it, not sure on that. What if he'd associated that shock with a child?
Two irish setters, sisters. Raised together and absolutely adored each other. Both got shocks going near the fence, but ont of them started to associate them with her sister. Again, she eventually attacked the other dog severely and from that point on the two dogs could never be kept together and the aggressor was rehomed.
And a medical issue too - something went wrong with the collar on a GR, the family came out to find the dog's neck bald around the two shock points and green pus there also.
For me, just those examples alone are more than enough reason not to get an electric fence - and there are many more besides. Those are the ones that just stick in my mind.
Could your friend perhaps invest in some stock fencing? You can get it at a reasonable price on ebay and it wouldn't block the view very much, only really the fence posts would do that.