Actually the rule was invented due to the fact that i used them to rule the last uber game where you and i were on a team.
Just about everyone has been owned by the super long range of the agents. The problem is that range ignores height when determining max distance. Since agents have a huge advantage when trying to kill them with range, the only viable way to encounter them is with melee. Although when they are up high with a +11 range, it takes a lot of turns for your average 4-6 movement char to get to them, which by then, 3 agents doing constant pot shots with 4 attack dice, makes a melee char almost impossible to engage an agent. He who has an agent up high in a central location ownz the game.
Limiting the max range on an agent to 7 nerfs them a little, and restores balance to the game. At 100pt draft, they are just to powerful with standard rules.