IMO the smiling assassin could be coming about by the way you cant leave a neutral rating inside of seven days of the sale for a TRS.

When a buyer isnt fully happy but doesnt feel a neg should be left and cant be bothered to chase up a refund they decide to leave feedback and move on. Only option is wait till after day seven or give positive and mark down the DSR's.

Ebay should block a low DSR with positive feedback inside of the seven days as well.