Well, the client sends subscriptions to electrum-frc servers saying "these are my addresses, tell me if there are any txs involving them." The client can send txs, like in Bitcoin; if there's something erroneous, like: If demurrage has changed how many coins the client has, and the client tries to send those coins it still thinks that it owns, the transaction will still be transmitted to an electrum-frc server which will use the "sendrawtransaction" RPC command, which will return an error because the tx is invalid. Whether this will be reflected in the client, I'm not sure of ATM. I need to