Not the trophies awarded from one individual to another, but the ones here: http://www.chess.com/site_trophy_list.html that are voted on and awarded periodically.
Have a look back at some of the results and you'll see some pretty blatant evidence of vote lobbying (Will_Smith, an account that is now closed, for all but one of the trophies in October of 2008?). I'm suggesting that a feedback system would not only be open to the same type of abuse, but that it would without a doubt occur and either become completely useless as a metric, or another giant distraction for the staff from an enforcement standpoint.
... the abuse that occurs with the site trophies ...
?