It’s when the Coast Guard’s mission included RESCUE. It no longer does.
Get in trouble in a boat and call the USCG. If they respond by radio on 16, see what happens.
You are better off joining a HAM club and getting on their net.
The History Guy remembers Rescue Flotilla 1 of the US Coast Guard during D-Day. It is history that deserves to be remembered.
What are you implying their response - or lack thereof - is for distress calls?