No. The votes for witnesses are weighted by the SP holdings of the voter. @freedom, for example, votes for @pumpkin for witness, and @freedom has enough SP that his/her vote is reported by @aggroed to be almost 30% of the votes for @pumpkin for witness.

What this means is that an outside party wishing to control the witnesses only needs to buy enough Steem to outvote the rest of the community, in order to completely control the witnesses.

This is a Sybil attack.