[ODE] collideAABBs question

[Matthew Hancher]

Hey all.  At the start of the collideAABBs() function, it checks to make
sure the two geoms don't belong to the same body:

   // no contacts if both geoms on the same body, and the body is not 0
   if (g1->body == g2->body && g1->body) return;

Why does it only early-out if the body is not zero?  It seems to me that
if both bodies are zero then we *really* don't want to bother with the
collision.  Am I missing something here?

(I realize this is a nitpicky question, but I stumbled upon this while
profiling my code and got confused, so I figured I'd toss it out.)

mdh