If you knew anything about dogs you would know that's entirely possible. But it's only one of a few possibilities imo
Rubbish - we only have Luke's word that Mia didn't detect anything along the path on the way to meet the 3 others.
Plus, if you knew anything about dogs, they don't need to be told by a human to be in any kind of mode in order to smell blood.
Oh and Marty - Sandra's here - you can ask her directly about some of the things she said last year about the Mitchell's and of some of the behaviours that gave her cause for concern. Or are you going to miss the opportunity, so that you can harass me when she's gone?