Not really surprising for two reasons. One is the USMC takes this sort of thing VERY seriously,and the people who even get accepted for Scout and Sniper School are not "typical Marines" in any sense of the word other than they do wear USMC uniforms.
The other factor in this equation is that Quantico is where the USMC trains Marines to become USMC officers,and the typical trainee has little,or no field combat experience so they don't know what to look for,or even how to look. In situations like this,you don't even use binoculars until you start looking off into the distance,and what you look for is movement,not a man. You look for little things,like a section where the grass is moving contrary to the direction the wind is making the rest of the grass move.It might be subtle,but it IS there and it CAN be seen if you understand what you are looking for and know HOW to look.
And in the real world,a couple of you are going to die before you even know he is anywhere around. THAT will be how you know he is there,and give you a general indication of which direction to look. After finding proper cover,that is.
