I cannot, just cannot understand why people think they can take on a dog and then just give it away so lightly. It makes me so sad - surely your dog is a family member? I would no sooner give my pets away than give my children away.
At the start of last year, when I was pregnant, I read up everything I could to make sure our dog and our cat would be affected as little as possible by the new arrival. I didn't want them to feel jealous or shut out any more than I wanted my two girls to. I just don't understand people who think "oh, baby on the way, let's discard the dog". The dog is family.
Sadly, I lost the baby 
and that's why we got our 2nd dog Poppy :). She was my lifesaver, the silver lining to a very black cloud. But in the unlikely event another real baby ever does happen, I would never, ever regret getting her, and never let her feel usurped.
Plus I see so many people who say "the dog did this, it has to go" (some minor misdemanour). Are your kids never difficult, then? We had a bit of trouble a couple of months ago where Poppy was attacking our elder sheltie. A couple of friends said "why don't you take one of them to rescue? It's too much like hard work." I didn't react well, I can tell you! We got them checked at the vet for any problems, got in our dog trainer for help and worked to overcome the issues. Things are now much, much improved. You don't give up on your children when the going gets tough and I can't see the difference. You've taken on this life, it's your responsiblity to make sure it's a good life, from start to end.
Sorry for the rant! I just don't know how this can be got through to people so they don't see their dog as a disposable commodity. More campaigns like the "a dog is for life" one? I think educating people is probably the only way to make a difference, but educating people is expensive.