  Analogue Hawking radiation from acoustic horizons is now a well-established
phenomenon, both theoretically and experimentally. Its persistence, despite the
modified dispersion relations characterising analogue models, has been crucial
in advancing our understanding of the robustness of this phenomenon against
ultraviolet modifications of our spacetime description. However, previous
theoretical approaches, such as the Bogoliubov transformation relating
asymptotic states, have somewhat lacked a straightforward physical intuition
regarding the origin of this robustness and its limits of applicability. To
address this, we revisit analogue Hawking radiation using the tunneling method.
We present a unified treatment that allows us to consider flows with and
without acoustic horizons and with superluminal or subluminal dispersion
relations. This approach clarifies the fundamental mechanism behind the
resilience of Hawking radiation in these settings and explains the puzzling
occurrence of excitations even in subcritical (supercritical) flows with
subluminal (superluminal) dispersion relations.
