We study a multi-leader single-follower congestion game where multiple users (leaders) choose one resource out of a set of resources and, after observing the realized loads, an adversary (single-follower) attacks the resources with maximum loads, causing additional costs for the leaders. For the resulting strategic game among the leaders, we show that pure Nash equilibria may fail to exist and therefore, we consider approximate equilibria instead. As our first main result, we show that the existence of a $K$-approximate equilibrium can always be guaranteed, where $K \approx 1.1974$ is the unique solution of a cubic polynomial equation. To this end, we give a polynomial time combinatorial algorithm which computes a $K$-approximate equilibrium. The factor $K$ is tight, meaning that there is an instance that does not admit an $\alpha$-approximate equilibrium for any $\alpha

Nurse Dina Sarro didn't know much about artificial intelligence when Duke University Hospital installed machine learning software to raise an alarm when a person was at risk of developing sepsis, a complication of infection that is the number one killer in US hospitals. The software, called Sepsis Watch, passed alerts from an algorithm Duke researchers had tuned with 32 million data points from past patients to the hospital's team of rapid response nurses, co-led by Sarro. But when nurses relayed those warnings to doctors, they sometimes encountered indifference or even suspicion. When docs questioned why the AI thought a patient needed extra attention, Sarro found herself in a tough spot. "I wouldn't have a good answer because it's based on an algorithm," she says.