Incentivised/Proxy Withdraw to hide identity of key holder

[HarryR]

As with all Ethereum transactions the address submitting the transaction can be used to trace origins and destinations of payments, however the ring signature will still reduce linkability to a 1/N probability between each sender and receiver.

With the account abstraction improvements expected in Serenity it will be possible to sever this link and enjoy much stronger practical anonymity guarantees, but this isn't ready yet.

With incentivised / proxy withdraw you can let somebody else submit the Withdraw message in return for an amount enough to cover the Gas costs and their time.

The problem is a fluctuation in the Gas price could make it cost more for the submitter than the incentive is worth. The tx.gasprice global variable exists, but the sender needs to verify the transaction can be completed at the current gas price and doesn't revert() (which will cost them)