From the article, the L1 Lagrange point isn't stable, it's a saddle. In the plan described here, the craft would be actively controlled to adjust how much ligh

From the article, the L1 Lagrange point isn't stable, it's a saddle. In the plan described here, the craft would be actively controlled to adjust how much light they're diverting and at what angle in order to stay balanced at the Lagrange. If the steering system is turned off all the reflectors would harmlessly blow away.