Chaos: Yes :) I must say that I am not too put out by all this, as Jim says below it is only a game!
But it is slighlty frustrating, and I am sure for many others (not just in espionage), when you have worked hard to climb up the ratings to have someone (not their fault) leap frog to the top.
The BKR ratings are important. Having a tight BKR range at the top promotes competiveness and moral. However, where someone has leapt in with an extremely high BKR rating, causes abuse (defend rating by only playing low rank players) and creates less competiveness and frustration amongst others.
Sometimes that new rating is unassailable (a 500 point difference) , and I can't really blame someone from defending that position that they were luckily awarded (by playing only weak players).
I believe that anyone near the top of the ratings should have earned it over many games.
As Lukulus says the rating will drop rapidly if some losses are incurred. However, this is only true if those losses occur soon after the initial provisional BKR has been awarded. After about 10 games, the BKR delta is much less sensitive.