In a current sequential game im playing, 42939, i am teamed with a new player that misses his/her turns but is missing them not because he/she does not sign in, but because he/she signs in at the wrong time, he speaks in the game chat before and after his/her turn.
Im not sure if it has been suggested before, but email notification of turns for new players would fix this and lead to less deadbeats and fix this problem.