In terms of recovering costs.....I'd hate to think what might have happened in USA in the aftermath.
A/C delayed and incurred large costs in reconfiguring it for pax flight: plus crew disruption plus fuel & landing/handling fees etc. etc.
Innocent pax delayed and perhaps missed important events/meetings etc. or on-going flights with same consequences.
Innocent pax has benign baggage destroyed including contents.
9 injured pax who had to slide the not so slippery slope perhaps unnecessary. Some who now might be off work & unpaid etc. etc.
Who do you sue? The reporters of unfounded suspicions? The pax who lost their baggage? The airline?
Not that I support in any shape or form the 'suing culture' but some might take umbrage after this event. I understand that in this day & age some people can become paranoid and see sinister shadows everywhere, but life will become very tedious if every sniff & sneeze is construed as a 'terrorist threat'.
As 'thf' alludes to: what if the conversation overheard was between 2 BBC reporters who had been covering a story about terrorist activity. Imagine what words their chit chat would include.
Were the suspicious pax spoken to by the CC's, and was it tried to determine if they posed a threat; or is that a no no? Imagine the scenario of 2 BBC reporters, who might well look like they came from eastern origins and spoke the language fluently: it is easy to imagine eavs-dropping pax conjuring up ideas. An approach by the CC's might reveal the truth before such consequences.
CC's are trained in calming irate pax and averting air-rage. Are they given any training about these scenarios? Crews are trained in assessing possible bomb threats, but that is when they are deemed credible. But rumours......?