This is a problem that has been around since the ArmA 3 Beta, roughly a year ago, and it still hasn't been addressed, and this problem is caused due to the poor implementation of 3D scopes.
As i'm looking down a sight while using my TrackIR, i can still look around. While this isn't that much of an issue if i'm using sights with no magnification, i becomes extremely frustrating and confusing when this happens with an MRCO, RCO, ARCO or the worst of the worst, a sniper scope. I can look around, and the view outside the scope is magnified to the degree of the magnification of the scope. This makes no sense! Either lock the player's view when ADS or make it so the view outside the scope isn't magnified!
I know this problem was reported way back in the day but i couldn't find the old ticket, maybe it was one of those ones marked as resolved, but it never really was.