Sorry if this is mentioned elsewhere, but with with Chinese pools refusing to stop SPV mining, and all these "stress tests" going on right now with the double spending warning up... What are the odds of a double spend occuring? Does a double spend somehow duplicate the Bitcoins being double spent, or does one party get screwed over? Here is a list "The latest 200 double spends (10 Minute Cache)"
https://blockchain.info/double-spends only 1 of which (.5% of list at time of this post) in 2014 and 195 of which (97.5% of list) happened this month! Have the Chinese figured out how to successfully double spend using all their hashpower? Is this what is causing the BTC price to go up, due to manipulation? Should this be means for concern for the entire network, since the biggest pools refuse to comply with stopping SPV mining???
Double spending means that the same inputs have been spent 2 or more times. In this case, most of the double spends are from the spam attack which sometimes will send 2 transactions that have the same inputs. A double spend does not duplicate the Bitcoin, but rather screws over one party, the one who the Bitcoin should be sent to. The reason people suggest waiting for a couple of confirmations is because it becomes much much harder to double spend once the transaction is confirmed.