Walkers will lock on and shoot at players through walls, giving away their position.

[Baitster]

Occasionally, Walkers will lock on and shoot at players through walls, giving away their position. I have noticed this usually happens when enemy players are at the shops. A perfect example of this is Match ID: 9403319. Spectate "On" (Lady Geist) around the 14:00 mark. The Walker locks onto the enemy Kelvin and gives away his position. The Walker doesn't do any damage to Kelvin- it just makes the enemies aware that he is there.

 

[offsetcyan]

This also happens with minions, where they'll pathfind to a player who didn't aggro them through walls to give away their position.