No true Scotsman. It's a fallacy, dontcha know?
It's only a fallacy when the "true" nature of Scottishness simply
cannot be specified by any rational means. If it can, then we can indeed have a "true" or "false" Scotsman, and it's no fallacy.
"Christian" is very specifiable, in a way that son-of-Scotland is not.
How about an internet forum?
Ha. To preen on an open, unmoderated internet forum is surely one of the lowest achievements a person can have. It's pretty much just one step ahead of winning a video game.