The petition gatherers had laptops with the registration info. My brother was not on the list so they would not let him sign. He went and registered then went back.
That is why the signatures were 94% valid.
To the circulators, I say well done! This is an extraordinary percentage. To begin with, most people have no idea what Senate district they are in. Some, like your brother, can’t remember if they are currently registered. Using computers was really smart.