And just because a dog wasn't aggressive with its previous owners doesn't mean it won't be aggressive with the new ones. My ex and I inherited a German Shepherd when we bought our first house. He was a baby guy with the other family, so they said and I had no reason to doubt them, but he was extremely territorial and cornered me twice, and lunged after one of the kids, before I called them and told them to come get him.
They acted all put out and tried to convince me to give him more time. I told them come get him or he was going to the pound. Can't take the chance on that stupid dog hurting one of us while he was "settling in".
So, anyway, just because the dog wasn't aggressive with Catt or JWWB doesn't mean it wasn't aggressive with Mike and Bay Kat.