We show that team automata (TA) are well suited to model secure multicast/broadcast communication with possible packet loss. This is a consequence of the natural way in which one-to-many (one-to-all) transmissions typical of multicast (broadcast) sessions can be modelled as communications between the component automata (CA) constituting a TA. In addition, we investigate a formulation of the Generalized Non-Deducibility on Compositions (GNDC) schema in terms of TA with the aim to embed TA in this well-established analysis framework. We intend to use this new setting for the formal verification of security properties for stream signature protocols. Finally, we use TA to model an instance of the EMSS multicast protocol family.