This is a surprisingly easy mistake to make.<p>Background: I was one of the original engineers on the Goal Line Technology system now used by the vast majority of professional leagues.<p>Heads are surprisingly ball shaped from a a lot of camera angles, and the male balding pattern conspires to give a good impression of different football graphical designs.<p>When we were developing the system, we thought we had ball detection pretty nailed, and we never had false positives from any of the heads of engineers on the team. Then, our boss came to test the system ... As far as our algorithms were concerned, his head was exactly a football, just as in the article! Highly embarrassing, but everyone saw the funny side. It gave us better data and inspired a few more robustness checks that ended up being crucial later on! :)