This is critical against some bots, as they use their worker scout to attack in the beginning of the game. If nothing is done the enemy worker will start to kill off our workers. Our worker either needs to keep it busy by chasing it, or if you can lead it a bit (ie move just ahead of it, probes tend to be faster than SCV's) to attack.
Walling can prevent the enemy scout from entering, if the chokepoint is small enough, ie it only takes 1 or 2 supply depots to wall it off, otherwise we will have to be prepared for this.
The SCV can still gather as normal, but if the enemy scout starts attacking a building (like the command center) or another worker, then it needs to represent.
This is critical against some bots, as they use their worker scout to attack in the beginning of the game. If nothing is done the enemy worker will start to kill off our workers. Our worker either needs to keep it busy by chasing it, or if you can lead it a bit (ie move just ahead of it, probes tend to be faster than SCV's) to attack.
Walling can prevent the enemy scout from entering, if the chokepoint is small enough, ie it only takes 1 or 2 supply depots to wall it off, otherwise we will have to be prepared for this.
The SCV can still gather as normal, but if the enemy scout starts attacking a building (like the command center) or another worker, then it needs to represent.