Shaddows - 1:00 pm on Sep 7, 2009 (gmt 0)

is it possible that the Google employees themselves don't know exactly how the SERPs will be affected

Nailed on certainty, more like.

Thats why every major update has a series of aftershocks, as unforseen problems are fixed, patched and bodged.

And also why Caffeine specifically asks for feedback.

Its like saying, "don't meteorologists know the impact on weather if you rearrange the ocean currents". Thers no way to accurately predict results given current ocean currents (or SE algos), let alone what will happen if a major componant changes.