Existing iris scanners can be deceived by pictures of other people's irises. I do not doubt that facial recognition will be fooled by people making masks (to fool infrared scanning).

http://www.schneier.com/blog/archives/2012/07/fake_irises_fo...

http://www.bbc.com/news/technology-18997580

The basic principle of biometric reading is the equivalent to sliding your photo under the door to a guard. The guard checks the photo against an already existing set of photos and lets you in. They don't check that the photo is of you - which is a common failing when you let marketing design your security.