BTW (from their official Universal website):
What information is collected as part of the finger scan?
Using a scanner, the software scans swirls and arcs of the finger to create a grid of intersecting points. These points are then stored as a series of coordinating numbers only. When the finger is scanned again, the number series will repeat and match itself to the stored original. As this information is stored as a number only, a fingerprint image cannot be recreated from the stored information.
Are all guests required to submit to a finger scan?
If you don't want to submit to a finger scan, please notify the attendant at the entrance. You will be required to carry and show a photo ID.