> But clearly in their design of the system they hadn't considered it. They might well have considered it the possibility of duplicate tags in the same flight

> But clearly in their design of the system they hadn't considered it. They might well have considered it the possibility of duplicate tags in the same flight plan but since identical tags are supposed to geographically distinct, they probably didn't further consider a flight plan where the entry and exit points from the UK (which is a relatively small airspace, I think) are the same tag (since it sounds from the report they did that this was an extremely weird flight plan.)