Pnina,

Knowing a bug exists and having a recipe for it are two completely different things. When trying to fix bugs in my own software products, it is substantially easier if I have a recipe for fixing a bug, than if I don't have a reliable way of creating the bad behavior-- and thus testing my fix for it.

Another way of looking at it is: Just because a recipe doesn't exist, doesn't mean the bug doesn't exist. It just may be harder to identify what causes it. Once the cause is known and reproducable, typically the resolution is much simpler.

It sort of like cars. Your car makes a funny sound, you take it in to the dealer to fix, but now the sound is gone. The dealer is sure you're telling the truth about the sound, but cannot figure out how to fix a sound, unless he can reproduce it.

HTH,
Chipp