We purchased our park hoppers from Ticketmania and they send a photocopy of the backs along with the tickets. DH lost 2 while we were at WDW last year, and we took the photocopy, they voided the lost ones and issued new ones in about 30 minutes. The CM said "whoever told you to photocopy the backs, that was the best thing you could have done".
The biometric scanning only measures the outline of your 2 fingers, it's not a fingerprint scan, so it isn't a means of ID to find ticket info.