Wat kan en mag men op internationale wateren?

Ik ga helaas een stuk Engels gebruiken in mijn antwoord, die juridische tekst is wat lastig te vertalen.
In de San Remo Manual on International Law Applicable to Armed Conflicts at Sea, in de paragrafen 67-68 staat:

67. Merchant vessels flying the flag of neutral States may not be attacked unless they:

(a) are believed on reasonable grounds to be carrying contraband or breaching a blockade, and after prior warning they intentionally and clearly refuse to stop, or intentionally and clearly resist visit, search or capture;
(b) engage in belligerent acts on behalf of the enemy;<
(c) act as auxiliaries to the enemy s armed forces;
(d) are incorporated into or assist the enemy s intelligence system;
(e) sail under convoy of enemy warships or military aircraft; or
(f) otherwise make an effective contribution to the enemy s military action, e.g., by carrying military materials, and it is not feasible for the attacking forces to first place passengers and crew in a place of safety. Unless circumstances do not permit, they are to be given a warning, so that they can re-route, off-load, or take other precautions.

In dat licht vindt Israel zijn legitimatie in de zeeslag van vandaag. Daar komt nog bij dat de Israelische marine eerst heeft geprobeerd ze te laten omkeren. Tevergeefs.
Ook ik wil dit bloedbad geenszins goedpraten, mijn antwoord is juridisch bedoeld.