That circle does show up for me, but just that alone I feel isn't quite enough in most situations. Without a clearer indication of the raiders' area of prevention, you have to physically check where something can be placed instead of just being able to tell by looking, which takes a lot of time in a game where quick thinking and action is key to success. I kept trying to place traps, only for the raider to block that tile the moment I actually clicked, and it felt a little frustrating :(
I'll have to check out the new build when it drops!