Unlike all the other comments discussing charges, this one actually has a good point. Presumably the safety driver is there specifically to prevent this from happening. They'd still have to show that the driver was personally at fault. That would mean showing that the driver was e.g. sleeping/not paying enough attention, or something similar.

At the very least, it might call into question whether safety drivers are actually providing any real safety. Localities may start to crack down on using that kind of excuse for self-driving tests.