The advantage

I think I might see your point.

While you are more likely to hit a robot at 0 if you only aim at 0. Also if you aim at -0.5 to 0.5 you are more likely to hit 0 then if you aimed at -1 to 1.

The reverse is not true. If you aim -1 to 1, you will be just as likely to hit that robot as a robot that moved -1 to 1. This is a bit counter-intuitive (to me). But I never actually studied probability. But it does make sense in a way.

But wouldn't your chance of hitting increase if you only targeted the gfs that an enemy robot actually went?

But that would be more of a fuzzy logic gun (it is usually somewhere in here) then a random gun. It enters into the realm of a real gf gun if you fire at gfs locations where the enemy is more often.