Can you imagine any b and b owner saying to any of their guests that they can't share a bedroom and they have to guarantee that there will be no "carnality"?
This is the relevant section of the interview:
"I asked if he would agree with Chris Grayling's position – that the bed and breakfast owner had the right to turn them away. Mason's argument took a complicated turn at this point, raising the possibility of separate rooms and no carnality on the premises, but eventually he said, "It's a tricky one, I have to say. There's a conflict of rights. The truth is I'm not sure where I stand on this. I was warned to leave it alone by my party."
No wonder the SNP told him to keep his mouth shut on this issue.