During a D-Day rehearsal in England, some 800 GI’s were killed when everything, for a whole bunch of reasons, turn to s**t. Ike ordered the news completely suppressed...and correctly so...it took decades until the families learned what happened to their loved ones. But could that happen today? Not a chance in hell..
You are referring to Operation Tiger, one of the dress rehearsals for the D-Day invasion. On the first day of the exercise, there was a friendly-fire incident because of communications problems and on Day Two, German E-boats attacked a convoy of LSTs, escorted by a British corvette.
There were reports of the incident in Yank magazine in July of that year, so the debacle wasn’t completely suppressed. But is was conveniently forgotten, and the families of many victims didn’t learn until years later that their son or husband died in a training accident, since the casualties were released along with those who died on D-Day.