Scenario: A group is in a room and the Druid amongst them casts the spell "Pass Without Trace" on the whole group, boosting their Dex (stealth) checks by 10. There is nothing in the room to hide behind. Moments later the door is kicked in and a gang of hobgoblins is looking right at the group. Can they be seen? Can they hide?
Now correct me if I'm wrong, but my interpretation of this spell is a boost to stealth, and not much more (it also grants the ability to not be tracked except for by magic, but that's irrelevant here). So if the group rolls a stealth check and the goblins roll a perception check, the goblins have the chance to see the group. I'm pretty sure of this. Where I'm less sure is if the group even has a chance of hiding with no boxes or beds or anything to hide behind. Even if they roll a natural 20 on their stealth check (boosted to 30 with the spell), do the goblins have to roll perception, or can they naturally see a hulking druid and 3 dwarven fighter allies who are just standing in the room?