over time it should return to a 'fair' position, once temporary disequilibrium in the 'crowd' (induced by marketing, hype, whatever) is resolved. It's a shame people vote 'strategically', not to reflect their true sentiments - but whatever. Over time, with a diverse enough crowd, 'wisdom of the crowd' systems are effective and reasonably unbiased.
doubtless IMDB will enjoy the free publicity.