Except when it is accidently disvovered because the fraudster shoots a bunch of people. Or when 8 or 9 hundred illegal aliens scheduled for deportation are "accidently" awarded citizenship instead. Or when the government rushes to make hundreds of thousands of immigrants citizens just in time for them to vote for Democrats.
Link: http://www.king5.com/news/local/investigators-may-probe-cascade-mall-suspects-citizenship-status-voting-record/327490798