The South African Revenue Services implemented e-filing two years ago, with great success. Most income tax payers can file online in minutes, using information gathered from employers. IIRC, the number of tax Rands gathered rised significantly.<p>Obviously, fraud can be commited by omitting income generated from non-registered employers or informal employment, but as far as I know, they keep quite close tabs on people's bank accounts.<p>One factor that contributed to the success of the initiative, is the ease with which companies can submit their employees details, using software provided for free by SARS.