These are some fascinating ideas.

Two thoughts:

1) Although it may be hard in "first world" countries to fake an identity nowadays, there are many countries where the record keeping is not as sophisticated, and where it's much easier to bribe officials if you want to bypass whatever record keeping is in place. Someone with a little patience could create (or steal) hundreds of legitimate looking identities...

2) Once again, you can have all the procedures you want to do something, but they have to be followed to be effective. One of the strange statistics of the recent mortgage meltdown is the charge that large number of sub-prime mortgages were awarded to people who were in the U.S. illegally - many of whom either used fake IDs or in some cases were not asked for standard forms of identification. Go figure...