Also, from the same article:

“The Secret Service and armed guards started telling us to leave, firmly,” said Barbara Maring, 42, who was finishing a tour of the White House with her husband and three children. She at first worried that the floor shaking beneath her was caused by a bomb. “Our kids won’t ever forget that experience.”

Imagine if they had been shaken at the Holocaust Museum. Then they’d *really* never forget, elephant-with-a-grievance style.