Actually, I think you are trying to be difficult, but whatever...
10% is just based off my past experience of following Intel. Granted, there haven't been many pre-earnings warnings lately until last quarter, but back during the growth days that was my estimate for a threshold. Again, looking at last quarter, they initially guided towards revenue of $9.1-$9.8B, and felt it was worthwhile to pre-warn when their new estimate was $8.7-$9.1B. This represents a midpoint change from $9.45B to $8.9B, which is a 6% drop. So if anything my estimate of a threshold to pre-warn might be pessimistic. Perhaps the drop in GM added some incentive to pre-warn.
Don't get me wrong, my expectations are very low for this quarter's results (and likely the rest of the year), but IMO those waiting in anticipation for more bad news before the earnings release can stop holding their breath...