Oh and before I forget that is a way to "exploit" the game in a way. Reason is it allows person a to work with person b in completing missions. Person A can't get into the server but Person B can. Person B deletes the file but doesn't have the mission thereby allowing Person A to complete for the reward with ZERO work done.
It's not exploit, it's more of service, and help from other players. Another way of interaction in game.