Pertinent to the discussion, some of the above mentioned "other ICAO guidance" happens to be the Warsaw Montréal Convention (1971) Convention for the Suppression of Unlawful Acts against the Safety of Civil Aviation, attached below.
Notable content relevant to the topic:
Article 1 para 1 provision (e)
Article 3
Article 4 para 2 both provisions (a) and (b)
Article 6
Article 14 para 1 - which signatory Byelorussian Soviet Socialist Republic did not accept (p. 19 of the pdf)
It's a short read but a lot of headache for Polish diplomacy.
Last edited by FlightDetent; 24th May 2021 at 13:37.