 Scholar Andrew Scobell agrees with Li Lu that student pickets were effective until June 3 in keeping the People’s Liberation Army (PLA) at bay; as between May 23 and June 3 the troops were ordered not to move on the unarmed students.Once authorized to use force, the PLA broke through student pickets and entered the square, demonstrating the inability of the pickets to resist the army.Once the crackdown began, the responsibilities of the pickets widened to include maintaining order during the square’s evacuation, as well as physically protecting the Defend Tiananmen Square Headquarters leaders, which facilitated the escape of Chai Ling, Feng Congde, Li Lu, and Wang Chaohua.