Today in People v Mothersell (2010 NY Slip Op 02677 [NY [4/1/10]) the Court of Appeals struck down the use of a search warrant which permitted the search of "all persons present" to justify 'visual' body cavity searches (I think this means the search was limited to visible body cavities) of persons at the scene of the search warrants execution who were not arrested and were searched solely based on the search warrant. It did not hold that "all persons present" search warrants are always invalid, but it did hold that the SW must demonstrate probable cause to search each person authorized for a search. The ruling would require substantial factual allegations regarding a location before permitting the conclusion that everyone there must be involved in drug activity.
Outside of such intrusive searches based on such limited justification, the language of the decision may be particularly useful as it ignored the "pages of boilerplate allegations" and instead focused on the "few relevant particulars", which in this case was was a couple of drug purchases from the apartment in question.
The court also rejected as insufficient to meet the "substantially probable" threshold an allegation that it is "not uncommon" that those present at an apartment where drugs are sold "could reasonably be expected to conceal cocaine". Finally, the court reaffirmed that substantial proof is required to justify a , even the ones you can see.