This is *withdrawals* from mt gox....under their current system they track withdrawals that they sent to users via the transaction hash. Which is apparently a f***** way to track them. So they should track the withdrawals via the input/output/amount instead.
It's impossible that two withdrawals would have the same inputs/outputs; provided that mt gox use change addresses.
How is it impossible?
MtGox doesn't control the destination address, so that can be the same.
For MtGox to control the origin address it means they would have to spam the blockchain with internal transfers to intermediate addresses (that they could change) for withdrawals, so that a given address is only used once for a given amount in a given time-frame.
By default an address is only used once, the entire balance on the address is spent and any leftover coins are returned to a new change address. Mt Gox has literally millions of addresses. Address can be used once then discarded. This is not "spamming the blockchain" this is just the way bitcoin works by design.
It's trivial for them to discard used change addresses.
It's very easy for them to ensure that the same inputs/outputs/amount are never used more than once.