certain types of bomb 'warnings' ought to be ignored
PaperTiger, as you will have immediately realised the problem then moves to "what types of warnings?", "who decides?" and "what are the criteria?".
Hence we end up back at the same point - who decides, who is responsible and who has the authority to act. Hence my original post (on which you commented) and the position I took. Several other contributors including
Sunfish above have taken a similar line. I see no way that the logic of the situation does not end up (and should not end up) anywhere other than with the captain.
P.S. Not that I am unsympathetic to your point that warnings are invariably false. The temptation to say something along the following lines is considerable: "With modern security methods we no longer consider that a real bomb AND a bomb warning are a credible probability. Accordingly, we will henceforth ignore any bomb warnings that are not sufficiently precise as to be credible". I was just wondering if you were going to make such an argument in a way that I had not anticipated. (While attractive it may have a couple of flaws).