[RPG] Can a PC be surprised if he expects combat before the encounter

dnd-5esurprise

In a Hunger Games-like fighting pit, a character knows he is fighting a rogue that will try to ambush him. This area is densely forested, but small, so the encounter will occur very soon.

If he is on high alert the entire time, would he still be surprised?

Best Answer

If he sees the Rogue coming, he's not surprised. If he doesn't see the Rogue coming, he's surprised. From the PHB, page 189:

Any character or monster that doesn’t notice a threat is surprised at the start of the encounter.

So it's not about readiness, it's about what you perceive. This is important, because players will often declare that they are on high readiness, or say that they always expect to be attacked. Unless you're happy with the player characters never being surprised, it's best to disallow this (unless the PC has the Alert feat).

As @MatthieuM points out, if you want to represent a state of active readiness, a good way to do this is to make Perception checks actively rather than just relying on passive Perception to see enemies coming. So if your player complains that his readiness isn't doing anything, this could be a good compromise.