Very much agree Dusty, the move away from checked bags is very bad for security (and queues to get airside).
One thing to get straight, the Captain is trained, entitled and obliged to judge the seriousness of a bomb threat discovered in-flight.
They are not trained nor entitled judge the 'non'-seriousness of a threat discovered in flight.
I've checked the guidance notes about the use of PIK and STN, they only get a mention due to their ability to handle dangerous goods; if these are hoaxes and being treated as such why PIK again.
SIDSTAR just a point to note, you say the Capt was refused permission to do what he was required to do - well that's always going to be the case, there are stock messages laid out for controllers to refuse permission on behalf of HM Gov't. Back in the days of traditional Hijacks (Ah, remember the good old days) you were refused entry to the country, some countries would put obstacles on the runway. As Capt you state your intentions and act on them, squawk the good squawk and land where you see fit.
It would be good to hear from anybody who actually heard the RT during either event to see how it was handled.