The Obama administration announced on Friday, May 16, 2014 that a person may be subject to a civil fine of up to $250,000 for knowingly and willfully providing false information on their health insurance forms in order to secure a subsidy to lower their cost of health insurance – these fines will also apply to persons lying to avoid the requirement to carry health insurance (or pay the shared-responsibility payment penalty).
If you lie on your health insurance forms due to a mistake (e.g. typo) and you did not intentionally falsify information, then the fine you would be subject to would be a maximum of $25,000. This fine can be waived if the explanation for the falsified information is reasonable and you acted in good faith.
The long and short of this is that you want to be as honest as you possibly can on any insurance paperwork to make sure everything is in good order so you are not intentionally exposing yourself to any fines and/or loss of coverage.