Loss of trust for the BBC in North Korea? As far as I know North Korea sees the BBC as an organ of the enemy anyway.
Having, in my student days, been involved in organising international tours, including, at the height of the Cold War, a tour for a group of visiting Russian 'students'. I am very conscious of how peoples memories can be very feeble when dealing with what they knew/didn't know, agreed/didn't agree before the event.
I suspect that the LSE is looking after its own interests and students who agreed to everything before hand in a state of high excitement are getting cold feet after the event in case it means they have blackened their copybooks with the LSE authorities.