Would you trust your dog if he indicated he didn't like some one?

My husband’s best friend died a year and a half ago. His wife just came by to deliver some chairs I bought from her. We invited her in to sit a spell.
Cato barked and barked at her and kept backing away from her. It was weird! But I guess he sensed something something about her that I don’t see.

What’s REALLY weird is after she left I opened up Facebook and front and center was an article that said it had been scientifically proven that dogs can sense bad people!

What are your thoughts?