Premise: The 1945 Major League Baseball All-Star Game was cancelled on April 24 after the Major League Baseball (MLB) season began on April 17. The July 10 game was cancelled due to wartime travel restrictions in World War II. 1945 is the only year since 1933 when the first official All-Star Game was played, that an All-Star Game was cancelled and All-Stars were not officially selected.
Hypothesis: travel restrictions caused the only cancellation