Foreign Bank Account Reports (FBAR’s) are currently policed by the US Department of Treasury’s Financial Crimes Enforcement Network (FinCEN). If you haven’t filed your Foreign Bank Account Reports yet, it probably makes sense to submit these sooner than later, in case FinCEN decides to impose penalties for late filing. Currently penalties only apply if the IRS chases you before you submit the FBAR (i.e. for “not” filing vs. “late” filing), with the harshest penalties imposed if they decide that you “willfully” chose to not file your FBAR (or you knowingly submitted an incorrect/incomplete FBAR).
KPMG has put together a pretty comprehensive report on the status of FBAR’s as of April 2018: http://www.kpmg-institutes.com/content/dam/kpmg/taxwatch/pdf/2018/mobility-matters-apr-2018-fbar.pdf