The failed negotiations I can recall are almost entirely the fault of my own failure to use interest-based negotiation techniques. Not listening properly, lack of preparation, allowing emotion to cloud my judgement have been the usual culprits when I have come away dissatisfied with the result of negotiation.
Hostage situations are exactly the ones where establishing a relationship is most important.
Unless there is an intrinsic relationship developed between hostage takers and 'the good guys', a relationship that enables the parties to develop good communication and trust, the odds are against a favourable outcome. Nonetheless, unless you treat people with due consideration of their interests, your negotiation is likely to be unsatisfactory. These techniques can certainly serve the immediate interests of parties taking those approaches. If you cheat me once, shame on you. If you cheat me twice, shame on me.