Does the Flytrap attack an invisible traitor, and must the traitor announce entering its room?

Question

Accepted Answer

Treat the Flytrap like a hero attack. The traitor does not have to announce entering the room, and the Flytrap's controller may make a blind guess that the traitor must reveal if present. Another reply argues the traitor should announce entry, so the point is contested.

Betrayal at House on the Hill (First Edition)

Does the Flytrap attack an invisible traitor, and must the traitor announce entering its room?