As no one knows the "Ticket Number" which was alooted to him, the game can be easily riggged.
I'm not sure but I think these "Ticket Number" will be published along with the future bitcoin block number
I will post back here when I found the references,
but probably
TheQuin keeps the info handy and can give you links and more details on it
edit: found it, one page back
We publish on Twitter a file that contains the number of the block that the hash will provide the client seed. That file also includes the server seed and ticket list. That's everything you need to verify the result.
What I am saying is that the ticket list can be easily manupulated by alloting the winning ticket to such an account that is either held by freebitco.in itself or is inactive since long time(there are thousands of such accounts at regular intervals).
So even if they assort the userids in ascending order and give tickets accordingly, still they have scope left for increasing the number of tickets of their favoured userid to win the lottery.