FamousPictures Magazine Source 

I did a little digging, and it appears that the story about the switchboard operator dying of a heart attack is a fabrication.  According to the cited page, operator in question was "the motel owner’s wife".  But the motel was owned by Ralph Abernathy, and his wife Juanita just gave a speech last month.  As far as I can tell FamousPictures Magazine is just another wiki, which suggests it should be trusted like any other Wikipedia editor... in other words, not at all.  I'm going to go ahead and remove all the material from that source right now from this and the MLK main page.