Someone I knew long time ago was from контрразведка (counterintelligence), concretely, from служба наружного наблюдения (field observation duty).

He bragged that Russia's (former USSR) counterintelligence was so sophisticated that higher ranks of spies from around the world all worked in Russia or USSR some time in their career. He presented enough evidence in form of mind experiment that I believe him (mainly due to his reaction time - he has answers readily).

So, for your "world's most sophisticated intelligence" I raise my "самая лучшая контрразведка в мире". Can world's best intelligence service be stopped by world's best counterintelligence service?

Otherwise we are going into pure speculation, like "spies agree on some kind of rule", etc.