Thanks for the reply. Agree that spam predictions will go up, if IRI puts incentive on earlier predictions. But, consider below 2 points.
1. As spam predictions go up, so do will go down, the spammers accuracy %. That will help the original poster differentiate good and bad predictors. I assume that is exactly the reason why IRI lists accuracy % in addition to number of correct predictions.
2. Currently people are playing with the IRI system. See that 27 out of 35 predictions on this PNR are made today when it...
more... is clearly a free hit. I suggest a button like "stop predictions now", available to the original owner poster and IRI admins(+revoke).
I assume fear of the "stop prediction" button might just push the predictor to predict early. Also fear of "poor accuracy %" will counter balance the spam predictions. May be I am taking IRI too seriously and should leave it as it is :)