May Search Warrants for Cell Phones Include Connected Cloud Services?

While preparing to teach a recent class about search warrants for digital devices, I spoke with a number of experts in digital forensics. Each conversation was very helpful. Almost all of them touched on an issue I’d never previously considered: whether search warrants for cell phones do or may include the authority to search connected cloud services. Example. To illustrate the question, imagine that the Bedrock police suspect Fred Flinstone of conspiring with Barney Rubble to sell drugs. They arrest a drug user, who tells them that he gets his drugs from Fred and that he communicates with Fred by cell phone. During surveillance, the police see Fred use his phone just before and during apparent hand-to-hand drug transactions. Finally, they have evidence that he’s working with Barney, and in their experience, co-conspirators often communicate using their cell phones. Based on the foregoing, the police seek a search warrant authorizing the search of Fred’s phone for evidence of drug activity including relevant communications, customer lists, ledgers, and trophy photos. Probable cause seems like a slam dunk. But if the warrant issues, may the police search connected cloud services while searching the phone? Would it be proper to embed in the search warrant a proviso along the lines of “including connected cloud services”? (I recognize that the term “connected cloud services” is not well-defined, but at a minimum I mean applications like Google Docs and Dropbox that may be installed on a user’s phone and that provide access to files and documents [...]