Bank runs are an inevitable consequence of fractional reserve meeting unpredictable and uncontrollable world crises, magnified by human panic and self-preservation instincts when confronted with such crises.

When a crisis hits, people will want to get their money back under their control, and banks are incapable to give the cash back due to fractional reserves.

For any bank, a bank run on it is not a matter of "if", just "when".