The trend is palpable. As Prof. Witmer-Rich (Cleveland State) explains in this post, a Delayed Notice
Search Warrant (aka: "Sneak and Peek searches" and "Black Bag jobs") involves "the police conduct[ing] a covert search of a home
or business when the occupant is away. Sometime
later, they give the occupant notice of the search—maybe days, weeks or months
(today, 90 days is most common)." Those interested in this issue should pull Witmer-Rich's forthcoming paper, The Rapid Rise of
“Sneak and Peak” Searches, and the Fourth Amendment “Rule Requiring Notice."