It's because the player models don't actually aim the weapon where they're looking unless they're ADSing. If you want to see what I mean observe someone in 3rd person who is using a lasersight on their weapon. The lasersight will ALWAYS be at the center of that persons screen, but in 3rd person you can see that that point is almost NEVER where their gun is actually pointed (visually). I've also seen some weird situations where bullets literally come out of guns sideways.
Yea this problem needs a fix.
The only way you could get around the bot aimbot ridiculousness in INS 2 was to cheese it with smoke grenades. But with the smoke rework this game has, the bots can often see through it when the players almost never can.
Also, the fact that turning your head effects the visuals of the smoke just shows how bad it is. The smoke is made up of 2d sprites that always face the camera. WHY ISN'T IT VOLUMETRIC!?