Bitcoins sent off-site to gambling sites such as satoshidice etc. that send back to the same address that the BTC were sent from will be lost. Silk Road wallet addresses cannot be used for sending 'from', only for sending 'to'. Localbitcoins requires you to fund your wallet there before you can fund a sell order so the bitcoins will already be on that site if you decide not to go through with the transaction. Libertas