Dave, I am not saying "liar" but I am very sceptical.
You make it sound a commonplace for members to have a Mudcat name, a real name and another fake one.
How many have you known?
It may be common among rock stars and pop. icons to have stage names, but not in the folk world.

If it is true, it would have been more honest to reply to Jim, "My name is Ian Mather. I never hid behind anything but I am still hiding behind anonymity because that is not my real name either."