I heartily agree with Ovid
about trolling getting out of hand! My take on something to consider might be to impose restrictions on monks with too much negative xp. This is the inverse of what we already do here: granting privileges to monks who gain xp. Maybe something like being restricted to one post per day as your xp gets worse? Although this implies that new monks will have to have some similar restriction (5 posts per day?), otherwize trolls would simply keep on creating new id's - does that seem reasonable too? I don't know...
I confess I can't come up with a great solution for this, but the problem does seem to want for one.