Its a bit like when AI-ing close to a Sun. The AI will take evasive action to avoid, but immediately tries to return to the set Waypoint direction, only to have to evade again .... and again .....and again. Nice thing is though: you don't get destroyed and sent back to your last save point. Private Wombat (Explorer Extraordinaire)
If a course is not plotted F2 just acts as "engaging cruise mode" for me. Avoids nothing: Suns, planets, asteroids, whatever .....