Or it could be that he did hear a whistle. When Sky replayed the incident, there did (to me) seem to be a whistle just after the hooter thing went off. He's perfectly placed to head that ball into the back of the net. If the referee didn't heard that other whistle (if there was one), then Ronaldo has to be sent off for a second bookable offense. If it is proven that there was a second whistle, then I do think he was hard done to. But those are the breaks. Let's be honest here; there are plenty of people taking whistles into games and trying to put players off. After this incident I expect there's going to be plenty more of this kind of stuff going. An awful lot of our fellow football fans are utter morons and every team has them by the bucket load.