If McCain manages to pull off an upset on November 4, would it result in violence?

While I don't know what McCain has left to throw - and the Intrade money and state-by state electoral breakdowns show McCain with long odds - the national numbers haven't officially sealed things off with less than one week to go.

The potential for violent reaction is not a legitimate reason to vote for Obama, but it's something I've been pondering, especially after witnessing the GOP Convention firsthand in September.  Given the pent up rage of some people, especially on the far left, the prospect of a third loss after two close and controversial losses in presidential elections would be difficult to digest.

If a McCain win was followed by violence, what would it likely consist of - localized pockets of venting?  Nationwide disrespect of the law?  

Or is the potential for violence overstated?  Would disgust and disillusionment merely lead to demonstrations?  Or would some people finally make good on their claims to leave the country?