Fair enough, although, I think a procedure change and a "transfer authority" function could easily cover this. The transfer function would basically be: original cuffer presses the transfer button, swipes his print, the receiver then swipes his print, and the transfer is done.

However, in a broader view, yeah, there are probably better ways than fingerprints handle keys once electronic locking mechanisms are introduced. Probably something akin to a 2-factor cryptographic mechanism.