What is this?
Here is an example:
Let's say you're the guy on point. - You're the scout, the guy who is supposed to be killed first, the guy who is supposed to spot (and be spotted by) the enemy. That's your role. -
You approach the side of a building in an urban environment. Of course, being a good point man you stop before you look around this corner and slowly creep forward to gain a field of view. You take out your binos and observe the street.
Suddenly a body appears right in front of your binos! You begin to panic, you know you're dead meat.
You manage to take out your rifle and are just about to fire when you realize: I should be dead by now, were this soldier the enemy.
Then it hits you. This is your squad mate, Bob, he is also interested in what's going on and decided to peek around the corner. You then turn around to find the whole gang sitting in the street with you.
WTF?
Observe object A:

Surely, this defeats the point of having a scout?!
My point is, I hate nosy people. You're a grunt, you don't need to see anything until you're told to shoot. Six men are more easy to spot than one man.
You could be doing more useful things like covering the squad's rear and sides in case of an ambush. If you all stop when the point man stops this stops you bunching up, and preventing one grenade killing you all.
So please, if you're a squady. Don't crest hills, don't peek around corners and don't jump in front of the point man.

