I have a friend from college who once told me that his communications teacher informed him that when radio call signs were first being distributed there was a world conference in London (the International Radiotelegraphic Conferences at the beginning of the 20th century). America sent a delegate who was instructed to get U for the western half of the country and S for the east. But when he got to London his cabbie got lost trying to find the conference and they arrived late. As the story goes, when he got there only K and W were left. Is this true?

EDIT: Changed conference location from Paris to London