It may be due to ADR (I think it is) as I believe the wheels must be fully within the line of the guards within a certain steering angle.
However, I think it has more to do with the ride height. As you turn the wheels and go through a large bump the tyres can contact the guard lip. This can cause cuts and more often than not will cause the guard to be damaged. I've seen some cop cars with guards bent at that exact spot - probably from this problem. By having the 'flare' or 'eyebrow' (?) the tyre is kept from snagging on the guard.
BA'1.5' Pursuit 290
Lightning Strike / Reflective Orange Stripes
'General' Dog - AP's German Shepherd and Best Mate - 02Dec1998-15Dec2003.
'Pepper' Dog - General's and My Little German Shepherd Sweetie - 1996?-02Apr2006.
'Sako' Dog - My Beautiful and Pretty German Shepherd - 2001?-23Aug2006.