D&D 5E Knowing of a threat without noticing it

[Rya.Reisender]

Okay, another tricky one:

The PCs know that enemies are coming and are ready to attack them the moment they appear. However, the enemies have the plan to ambush the PCs and they all succeed their stealth roll. Are the PCs surprised or does knowing that enemies are approaching already count as noticing a threat?

 

[Hriston]

It sounds like they're surprised. Being ready for an attack isn't the same as noticing your attacker immediately before combat.

 

[Imaculata]

You could venture into a dungeon, expecting to be attacked by monsters at any moment, and still be surprised by them.
So... no, I don't think expecting an attack means you can't be surprised.

 

[fjw70]

How do they know of the threat.

 

[Maxperson]

Okay, another tricky one:

The PCs know that enemies are coming and are ready to attack them the moment they appear. However, the enemies have the plan to ambush the PCs and they all succeed their stealth roll. Are the PCs surprised or does knowing that enemies are approaching already count as noticing a threat?

Rulings over rules. If they know that an attack is coming and are prepared, I would rule that even with a stealth roll the enemy could not get a surprise in. This is an example where it seems silly to allow the rules to override readiness. Now, that's only if the attack is imminent within a short period of time. Knowing that the enemy is going to attack sometime in the next 30 days would be different. You can't stay on high alert for 30 solid days(or even a week), so the stealth attack could come while they are not ready and I would allow a surprise to happen. In short, just use your best judgment on whether it would work or not.

 

[Rya.Reisender]

How do they know of the threat.

A PC (which the enemies consider a friend) lures them to the position agreed on. The PC actually failed his stealth role, so the PCs know of his position, but they don't know where any of the enemies are because they are all hiding successfully (though they could guess they are close to the PC).

 

[Maxperson]

A PC (which the enemies consider a friend) lures them to the position agreed on. The PC actually failed his stealth role, so the PCs know of his position, but they don't know where any of the enemies are because they are all hiding successfully (though they could guess they are close to the PC).

So that PC and the enemy are all together and the group knows that? If that's the case, then the PC with the enemy is a part of their group for purposes of surprise and has spoiled it for that side anyway. The PC with the enemy would count for noticing that threat.

 

[Rya.Reisender]

Even if the PC is not a threat to the other PCs?

 

[fjw70]

A PC (which the enemies consider a friend) lures them to the position agreed on. The PC actually failed his stealth role, so the PCs know of his position, but they don't know where any of the enemies are because they are all hiding successfully (though they could guess they are close to the PC).

I would say no surprise. However, the monsters still get your attack from a hidden position so get advantage.

 

[Maxperson]

Even if the PC is not a threat to the other PCs?

Yes. That has nothing to do with it. There's not some mystic energy in the game universe that is going to say, "That member of the group there is a traitor, so he doesn't count for surprise purposes."

The PC is a part of the group and noticing him is going to reveal the presence of the others, even if those others made their stealth checks.