I agree with you for the most part. My 8 y/o Mastiff is not separated from the family. He is a part of our family and loved deeply, nor will he be put down for one incident. I can’t and won’t explain what triggered his actions because I do not know. He has never reacted this way to his previous housemates or with my pittie for the first 6mths together or showed aggression towards other dogs or people. We use the crate n rotate method and they both spend time with us independently. We use baby gates to separate their movement from each other. It is working great this way and neither dog is left alone. Through my rant, I was trying to explain that there are times when unexpected things may happen and in some dogs parks people take untrained dogs out so the adults can socialize and do not watch them let alone supervise. As well as explaining how fast things can become ugly. I will not put my Pittie or Mastiff in a position to fail or be blamed for the actions of another dog.