But you assume that someone did, while its also possible that a number of people rated them low. So if your assumption would be wrong, then what does that make your suggestion?
I think any abuse of the system would be leveled out if the system is used by enough people. The thread rating system is outdated and does not stimulate users to rate. A 1 click jquery rating stars function works much better:
http://www.fyneworks.com/jquery/star-rating/