Just to state the obvious: to the extent that your conditioning paradigm has an effect, it will cause someone primarily motivated by gaining forum approval, if they state an opinion that garners disapproval, will reverse their stated opinion and claim some other motive.
Of course, if you don't actually care whether they are likely to reverse their opinion solely to gain approval, merely whether they are likely to say that that's what they're doing, then that should be OK.
I think people are more responsive to this kind of conditioning when they know they are signaling an agreement than when they actually have a disagreement, especially because downvoting makes the signaling appear useless to the signaler.
It's perhaps a bit late to kick this off, but:
What are your resolutions for 2011, if you choose to make use of that Schelling point for self-improvement?