During WW2 a junketing Congressman returned from the Pacific and crowed that US submarines were experiencing low losses because the Japanese were setting their Depth Charges too shallow. Newspapers published this and the Japanese changed their tactics. US submarine losses rose.
Remember the initial landings of US troops in Somalia? They were blinded by the camera lights of the horde of News Crews on the beach?
If D-Day happened today the media would post the time, date and place citing the “Public’s Right to Know” while waving a copy of the First Amendment. Anything for a scoop.