//Why would they have a scientist on what was effectively a parlour game show?//
Maybe for a balanced opinion?
A lot of people that watched these shows believed in this stuff.
I remember working with a Pakistani colleague and he read palms. He said to me "And you young lady should give up smoking because you are prone to cancer" I found out about 20 years later that breast cancer runs in my family. OK so it wasn't lung cancer but even so. I also (for a laugh) went to a palm reader in India who told you how old you will be when you die. I told him not to tell me.