I am all for the bounty system.
If it is to be implemented, the player who posts the "ad" needs to pay out of his own pocket.
I do not agree with the 3rd condition, but the other two do look pretty good.
What a perfect idea, actually. I sometimes get people who say "guys, go after Joffrey cuz he's too good" and nobody does, which disappoints me. This is perfect for exacting revenge. It would add more materiel to the overall gameplay.
When I say "gameplay" I mean watching your ass more. >:)