Roel van der Hoorn
Something I've never understood - is there ever a reason not to either claim Contessa or challenge the Assassin card if you only have one influence left? It seems like if you have no legit claim to stop it from happening, you might as well choose another anyway since you can't lose two influence regardless.
If you see every game by itself, then indeed one of those choices is the way to go.
However, in the light of all the games you play with the same people, sometimes taking the loss is not such a bad thing, if you wouldn't have won the game otherwise. This way you may get away with a bluff when you still have an opportunity to win in a later game.