On the other hand a bad gut feeling proves to be right often too. And I'm relatively sure it's not just confirmation bias :)
I often think that shy people are assholes at first. Now that I’m aware of that I try to test the shyness hypothesis first when I have that feeling.
So exploit it, it’s something humans developed for good reasons. Just be aware of the biais and use it as a good starting point for a behavioral interview.
To make them less "dangerous" it's good to be aware of them and stay doubtful about them to give anyone a chance to proof you better.
Reminds me of how I handed my phone to a couple once and wasn't sure if they'd scam me, but I willingly took the risk of loosing my phone to be able to help people when they ask.
They where honestly quite sketchy... I still wonder if they maybe just spontaneously decided not to scam me because they felt I was prepared for it.