It is possible that the node shuts down, while it is waiting for a transaction to be executed.
Perhaps we should keep a list of cheques and mark them as cashed / uncashed.
Then, when the node boots up again, he verifies his uncashed cheques and if, according to his preferences (which is now: always cash a cheque directly), he wants to submit a cheque which is marked as not submitted, he will first look in the blockchain whether this cheque is really not submitted.