Mexican Girlfriend Living Illegally in US

[brucem]

Looks like it may be a non-issue:

The US Supreme Court ruled in 2009 that you will not be charged with identity theft if you are using false documents just to work.

[source]: http://blog.lawinfo.com/2009/07/01/supreme-court-decisions-made-in-the-2008-09-term/

Interesting case! I hope for the OP sake she is being totally honest.