"that, for the raid to be justified, the warrant and the explanation must clearly reveal (a) that there was an urgent need to obtain evidence that pertained to a serious crime, (b) that this evidence could not possibly have been obtained by other means, or on another occasion, or without a surprise visit"
I'm certainly no expert in American procedural law, but I'm not convinced that a US federal search warrant has to justify an 'urgency' criteria, or show that the sought after articles could have been obtained by other means. What other means? I suppose they could have asked nicely.