anyone challenge himself from his another account will not be count as wager.[/color]
Because you are getting into trouble in the past determining about people using multiple account for your giveaway ( incident with halevivi/amiryagot), I will suggest that it will be better if you adjust the rule into that the wagering process will be counted only if you challenge the admin.
Having this strict rules will be pointless if someone use up a TOR nodes to make a multiple account and challenge his/herself since you wont be able to determine if they are the same person and ofcourse it will be easily abused in the end