Not CX but here in Oz: We had a checkie who boasted that he spent two hours every night reading manuals, rules etc and, certainly, he appeared to know EVERYTHING about the aircraft and aviation in general. I admit, he was a very good operator himself, but a shocking checkie. One of those guys who is invaluable as a trainer because of their ability and extensive knowledge, but totally out of control with the power that comes with checking. A flight with him was a continuous barrage of questions, often while you were busy. Typically he would ask stuff that could not be measured e.g. "When visual, how far horizontally must you remain away from cloud?" Me: "Er......far enough to see where you are going?" Him: "Not acceptable, you of all people being a check captain yourself, must know". Me: "Actually I do, but how do we measure it?"
He never got the message about keeping questions practical. One day after I gave him a line check I marked him down for 'Compliance with Regulations'. He had never had a grade of less than 'excellent' in his career, so was quite miffed at getting an 'only average' from me, the resident cowboy of all people.
His sin? He did not switch on the navigation lights, by day, in cloud. Cowboys one, Anal Retentives nil.