The fact that she didn't know it would target Eidolon, or any cape, should be a more ironclad defense. Like ultimately it's not likely to happen, but if her power ever does randomly target some other cape at random in response to a question not clearly related to that cape and she gets charged on that basis, well, ultimately whether or not she can actually be confined by the legal system is inversely proportional to how bullshit she thinks the charges are.
Did she even know after the fact that it was targeting Eidolon, other than by manually reasoning out "who was in Canberra then and Houston now?"
Also I still don't understand what actually happened in terms of why it affected Eidolon - has her designating a target ever caused an immediate effect on that target before? Was it an interaction with a thinker power Eidolon was using (if so, she should be doubly considered not at fault)