The fingerprint scan has been going on for ages, the only recent change is they now scan for adults and children.
To those that have issues with it, especially children (and often adults with small hands), here's a tip. The frequent issue with children (and adults with small hands) is their fingers are too small and they don't fully fill the scanner area so each time they place it on the scanner it is just different enough it causes the scan to be just different enough to return an error. Adults and people with larger hands normally fill the scanner area so it is the same each time and this isn't an issue as often. Have your children, or anyone with smaller fingers, put the finger on the scanner so the tip is touching the top each time. This should help the scan be the same, or close enough to the same, to reduce the number of errors. I've been using this technique with DGD and she never has errors when we go in the parks.
It's not a fix 100% of the time but it does help a lot.