California Code, Revenue and Taxation Code - RTC § 19170

(a) An income tax preparer that is subject to Section 18621.9 is liable for a penalty in the amount of fifty dollars ($50) for each acceptable individual income tax return prepared by that income tax preparer that is not electronically filed, unless it is shown that the failure to electronically file that acceptable individual income tax return is due to reasonable cause and not due to willful neglect.

(b) For purposes of this section, reasonable cause includes, but is not limited to, a taxpayer's election not to electronically file an acceptable individual income tax return in compliance with Section 18621.9.

(c) This section shall apply to acceptable individual income tax returns required to be filed on or after January 1, 2005.