In the Playpen case, the government activated malware on a site with 215,000 members, as of last February, and obtained Internet protocol addresses of 1,300 computers. Out of that group, the government said it has charged 137 people.
“It’s a lot of people,” said Colin Fieman, a public defender in Tacoma, Wash., who is representing Michaud. “There never has been any warrant I’ve seen that allows searches on that scale.
Michaud is arguing to have his charges dismissed on grounds that the government’s use of the tool violated the Fourth Amendment. Fieman argues that some people might have gone to the site seeking to express fantasies that, while repugnant, are legal. The site, he said, does not clearly advertise itself as devoted to child pornography. He likened the government’s warrant to a “general warrant,” referring to the British practice during the Colonial era of allowing government searches without any individualized suspicion.