  We show that for a particular class of quantum channels, which we call
heralded channels, monogamy of squashed entanglement limits the superadditivity
of Holevo capacity. Heralded channels provide a means to understand the quantum
erasure channel composed with an arbitrary other quantum channel, as well as
common situations in experimental quantum information that involve frequent
loss of qubits or failure of trials. We also show how entanglement monogamy
applies to non-classicality in quantum games, and we consider how faithful,
monogamous entanglement measures may bound other entanglement-dependent
quantities in many-party scenarios.
