I realize thumb prints or finger prints are used for some private or public companies to absolute identification. Retinal scans is another extreme method of protecting ID, but, to even concern such measures on public sites connected to the internet is not a good idea.

I can only imagine a thumb print being lifted from some security data base and used in committing crimes. It just not a good idea. The only defense is to prove there is no DNA that matches the thumb print, but, in some instances that won't work either.

An offline dedicated computer to store personal files is the only way any information is secure. But, just to be safe, don't let anyone with a thumb drive near it.