Doing the responsible thing is incredibly difficult right now, or even knowing what that is.
They don't fear it would effect tuition, they know it. For example, if I was an incoming freshman or sophomore, and I wasn't allowed to go on campus, I'd just do a DMACC year online. That would be a no brainer for sure. ISU has been steadily increasing enrollment for 20 years, they have increased increased services to support the student population, and the budget is continuously more reliant on tuition. If they have a 10k drop in students which seems entirely likely even with in person classes, I can't imagine what that would do to them.
Like it or not, this is the same motivation driving the AD.
As far as the AD getting sued, I'm guessing every ticket will be printed with a "If you use this to attend ISU events you're forgoing any right to sue" language on the back. Probably the same for employees and vendors.