This is something I’m not sure how to feel about.
Certainly, since her BAC was not at all her fault and prior to the arrest she had no reason to suspect something like this might happen, dropping the charges was absolutely the right thing to do.
But while she might not have felt tipsy, that doesn’t mean she wasn’t impaired.
Should she be allowed a drivers license at all? This might not be her fault, but if you cannot drive safely, you shouldn’t be doing it. It sucks, but road safety is kind of important. Can a battery of tests be devised to see if her alcohol tolerance actually is good enough that she’d be safe to drive?
I wouldn’t be shocked if she has an extreme tolerance to alcohol- if you make it internally all the time, it’s going to build tolerance. And if she never noticed an issue, genetic factors helping tolerance are probably breaking in her favor. But is it high enough that she’d be consistently safe to drive, or low enough that she’d notice when she isn’t safe to drive?