Few voters will express their true preferences and will go instead with 'the lesser evil' when they fear their option will be in a small percentile and discarded. It is not unusual to have systems where 5% is required for a party to get into the parliament, or for a nominee to get into preliminary rounds, etc. So one cannot expect a voting system to incorporate all voter's preferences if they are very small but a warm-up voting would reveal that the fringes that big media avoids covering can become popular.