Those saying "Walker could have got sent off" are doing so because we had a shite ref who wanted to give the opposition every chance of an upset. Had it been a none city player in the CL I doubt many would have said that could have been a red because it was a yellow card all day long. Still didn't like him diving in like that mind you, no point in risking it.
Valencia just committed a very similar foul, never even been mentioned it's a potential red card....