Here's one example I remember: The goblins were tasked with entering an orc camp that had previously been raided and pillaged by human adventurers. The goblins were to find any leftover treasure and bring it home. A palisade of wooden spears surrounded the camp, which I used as a barrier to get inside and as something for a Shrike Fly to impale goblins on (cool monster design, btw!).
Upon defeating the barrier, the goblins entered the camp to find a bunch of dead orcs being picked over by a murder of crows. I wanted to have the crows be disturbed by the goblins entering, and have a chance for them to fly up and swarm the goblins, cawing at them, and then flying away. I didn't want a full encounter with crows, I only wanted the goblins to have a chance to panic. It felt like a danger just for entering the area, which in hindsight maybe is an unfair situation to begin with? I didn't want to just declare they panic, either, so it felt like a danger roll without any action.
Do you think a grim favor roll would work here? Perhaps 1-2 means they panic, and a 6 means they get to be put into a good position somehow? Or do you think it sounds like an unfair situation to have something happen here before they have a chance to take an action in the area?