You're saying that dogs never get jealous of a new child or baby, which suddenly gets all of the love and attention formerly given to it?
Added to the owners being gone, and a "new owner" in the house, and you have a recipe for disaster.
No - I was referring to what I thought you were saying - that a new person was a new alpha, and a new baby was higher up in the pack. Jealousy is a real thing. However, I didn't interpret this to be the main point of your post, especially in light of your other comments on this thread.
Personally, I would love to have a bad-ass personal protection dog. However, I couldn't handle the continual battle of wills. I have that already with my 2 dogs, but since they are min pins, it's not a big deal if I let them have their way on occasion. So, my sig stands in for a schutzhund.