  We discuss the `no-clicking' event, which is harmful for legitimate users in
Bennett-Brassard 1984 quantum key distribution: We describe an attack where
no-clicking events are utilized in the same way as double-clicking events are
utilized in the quantum Trojan-pony attack. We discuss how to deal with the
no-clicking events. We discuss how to estimate the security of the protocol
against the proposed attack by using a formula involved with the fraction of
adversarial removals of events.
