I recall many years ago watching a BA Trident go around from about 200'at LHR in CAVOK weather. When the tower enquired about the reason for the GA, they were informed that it was the SOP if a GS flag appeared prior to touchdown. Whilst I can see the sense of that in full IMC and during an autoland, but when the vis was 30km plus and no cloud at all, then I'm a little less sure!
Mind you that was brought to you by the same airline that had a crew divert back to LHR on a shuttle flight to GLA, when the Capt discovered that his breakfast hadn't been loaded!!!