I guess she's using some kind of canine sixth sense about their vibe, or aura, or whatever one would call it.
Smell. It's all about the smells. And it has nothing to do with what you think smells good or bad. They
like the smell of sh*t and will eat it if they smell enough protein in it.
By the time you reach out to let a dog sniff your hand, they already know everything about you that they need to know.