Originally Posted by Flying_Duck

I already have my fingerprint in the "system" and since my iris scan didn't work, I really didn't give up anything new.

Ditto - To obtain my firearms permit, I was fingerprinted and sent through the FBI system.
My iris scan didn't work as well, I'm very tall and the machine couldn't get a fix on me, they had me lean down and the angle was wrong so they just decided to use my fingerprint.