For all those willing to sue Mt.Gox because we will be making trades void, please remember that criminality usually falls under "force majeure" by its externality (not like we would have ever wanted that), unpredictability and irresistibility (we resisted most hack attempts, this one was "strong" enough to go through).
This is an interesting stand on that.
In other cases I know, it varies.
If someone would say tap into your phone line and make your number call these high-payment numbers (that cost x10 or x50 more per minute), then it is no excuse and still the person needs to be pay the due bill.
Even if it is just a regular person, versus hackers and versus big telecom.
Not saying that this is good thing. This is probably bad that it works this way especially as phone (land line) user can't really be at all responsible or can at all defend from someone tapping into cables box near his home.
Same thing with viruses popular in older days which called a high toll numbers from computer modem - dialers. But perhaps there where exceptions, not sure how it worked in most jurisdictions.
Sleeping over it, I thing most juts thing to do would be if any hacked exchange in this position, e.g. mtgox here, would reverse trades, then refund all lost income to people gaining on the fall, then try to find and sue the hackers responsible or sue other responsible.
In mtgox case, I would "kill" the auditor already. And sue the crap out of him.
1) Was it a private auditor
brought in voluntarily by mtgox, or was it some forced, government thing to audit your company?
2) what with few people gaining with say @10 trades, @12 trades, @15 trades and so on