State law requires registration and education for anyone who charges a fee to prepare someone else’s taxes. Most violators don’t even sign the tax package they’ve prepared, to accompany the taxpayer’s signature. The taxpayer is on the hook for any mistakes. State investigators from the Franchise Tax Board penalized 77 violators last year, and a few received $2,500 fines. Now authorities are again scouring the state for offenders, many of whom promise a high refund and charge accordingly.