What the changes will mean:

U.S. tech companies will ignore the instructions stamped on the fronts of subpoenas urging them not to alert subjects about data requests, industry lawyers say. Companies that already routinely notify users have found that investigators often drop data demands to avoid having suspects learn of inquiries.

...“Later this month, Apple will update its policies so that in most cases when law enforcement requests personal information about a customer, the customer will receive a notification from Apple,” company spokeswoman Kristin Huguet said.

Law enforcement's use of subpoenas to get "non-content" information (like header information of emails, sender and recipient information, and phone numbers associated with the account) has massively increased over the past several years. These are the requests that the companies say they will notify users about.

There will be some exceptions, such as if the information pertains to a case where there is a risk of "imminent danger to potential victims, especially ... the safety of a child...."

Bottom line: User notification should be the norm with subpoenas for information. A judge, not criminal investigators, law enforcement agents or lawyers for the tech companies should be the one to decide if user notification should be withheld. If secrecy is so important, law enforcement can apply to the judge for a gag order or search warrant with delayed notification.