[Someone1234]

You could, but it is an IR camera, so you better have the IR characteristics of your 3D face match also. If you combine IR and visible light photography you actually get a layered face-scan which is VERY hard to fake (not impossible, hard).

e.g. http://produceconsumerobot.com/biosensing/content/Face%20fev...

[higherpurpose]

What if you just hack the webcam firmware - like celebrity hackers and FBI have done for years already?

[MichaelGG]

If you can modify firmware, you've probably already won. Unless the auth is done remotely and requires remote attestation, perhaps.