Hi all - i have an idea to stop people using stolen private keys:

1) A wallet monitors its addresses in a block explorer.
2) If a pending transaction appears that WAS NOT sent from the wallet: The wallet immediately creates an identical transaction (or possibly the full balance) to one of its other addresses (possibly with higher fee to prioritize it over the non-wallet transaction).
3) The non-wallet . fraudulent transaction would be cancelled / disappear from the block explorer and the wallet would know not to use that private key ever again.

Its just an idea, but i think its something we should seriously think about implementing in all wallets.

Feedback / criticism welcome.....