They got lucky this time yes, but that won't always be the case. (And indeed hasn't always been the case) As Sanescientist suggested above it might be that several actions associated with any child pornography use (And possibly the sums of money) were picked up and flagged up as possible associations with terrorism. It is possible that this information backed up the 'faulty' sources and provided enough evidence to authorise the raid. If this is the case then it would possibly increase the frequency of 'getting lucky,' but so far this is only conjuncture. However, the police intelligence that lead to the raids was faulty. The fact that they 'got lucky' is irrelevant. I'm not saying we should knock the police, but I am saying that we should question the protocols that lead to this situation occurring so as to try and reduce the rate of such incidents.