Alcohol and secrets aren't always a good mix. I was at Branch association dinner at Halton House earlier this year and after a lot of drinks a Sqn Ldr blurted out which agency she had been working for - to a number of people. Whether people remembered is neither here nor there, but I understand it got back to her line manager. Cue a rapid posting...
ETA in an earlier post at an Embassy I had to remove an Army Sgt who became free-talking after a couple of beers. He had been warned and once the Ambassador got to hear of his behaviour, it was untenable for the Sgt to remain.there.