The assumed alertness of the PCs, avoiding overly cautious gameplay to keep the focus on the action.
PCs are always considered to be as vigilant as their vantage allows when dealing with hidden dangers like traps, lies, or secret doors. However, this doesn’t mean they are always aware of hidden threats. Instead, the GM uses a gut feeling to decide how much the PC perceives based on their vantage and the type of tension the GM wants to build.
Each of the three levels of vigilance creates a different dynamic in the scene, a different view of PC competence and the danger of the world. These three levels are: hint, reveal, and strike.
Foreshadow with a subtle clue about a hidden element. The player gets a single chance to interpret the situation. They’re limited to just one to highlight the natural response of the PC and to keep things flowing. Player intuition guides the story forward. A correct response leads to a reveal or possibly bypasses the situation entirely.
Foreshadow with an obvious unveiling of an immediately imminent threat. The PC that becomes aware has one chance to react before the danger strikes. Character competence guides the story forward.
Make an impact move as the danger immediately strikes them. The GM assumes the PCs were not vigilant enough. The dangerous world guides the story forward.