I want to set up an event (to be specific, a show subtitle text event) to occur if the player has failed to scan a certain ship. How can I do this? Setting up an is-event-false condition that refers to an is-cargo-known event does not work.
While Droid803's solution should work, I want to point out your mistake here:
the condition you need is not "is-event-false-delay" but "is-event-incomplete" ... "is-event-false-delay" only works if the contion of the event returns as "false", e.g. the ship specified in a "is-destroyed-delay" did depart.
"is-event-incomplete" however triggers if the event did not come either true or false yet by the time it is checked, e.g. the event checks if another event with "is-destroyed-delay" condition has returned true or false, since the ship in the condition has neither been destroyed (true) nor departed (false), the return for the "is-event-incomplete"-check is "true" which triggers the first event. Would the ship have been destroyed or departed, turning the second event either true or false, the first event's "is-event-incomplete"-check returns "false", not triggering the first event.