for those who own btc with gox, it seems like the issue is going to be the extent to which gox "re-issued" bitcoin deliveries to customers bc the recipients lied and said they had not received it. if there were many double deliveries, then gox may not have the bitcoin to pay remaining owners all the bitcoin to which they are entitled. a few issues/questions come to mind:
1. why the other exchanges are not having the same problem
2. would mtgox be able to figure out which customers claimed failed delivery but lied, and were then paid twice.
3. it seems like the gox omnibus acct should net out even at the end of the day. double deliveries would raise red flags (one would think) when all has been netted
1. Gox uses a customized wallet, which is obviously faulty. Other exchanges either implement it correctly (checking the address balance), or simply use standard bitcoind
2. Yes, if they have kept all the transaction and conversation log.
3. Not sure what you mean. But if gox really double paid some customers, they are the one to absorb the loss (or they will close and run)