To prevent individuals from getting into a situation were they have a high negative score, I would recommend that after a certain negative score is obtained, (? around -200 ?) the individual is unable to make any new replies in sections that have 'ranked threads' .
Once individual raises their score through voting, journal entries, 'the game', e.t.c ... they are able to resume replying in 'ranked threads' until their score drops back below the threshold.