What are these called in English?
What are their official job descriptions?
What do they do besides trying to make sure the musicians/athletes don't defect?
I have tried to google different combinations of North Korea/Soviet/Belarus, musicians/athletes, defecting and handlers/caretakers, but I can't seem to find anything useful. If anyone either has a good search phrase or know of a biography describing someone who managed to defect during a visit to "the free world", that would be very helpful! I am writing about a made up dictatorship, and feel I know too little about this, especially since I am planning on having one of my characters defect.
ETA: A very big thank you to everyone who answered, you have been of immense help! I thought I just might add what I have found using the information I got in this post, in case someone else needs this information. :
The dictatorships (North Korea and USSR) used words like "assigned travel companion" and "wet nurse" (mamka) to describe the handlers. I haven't found a more polite English word for them.
General information about how anyone defected was hard to find, mostly the defectee refused to tell about their escape to protect the people who had helped them escape. I did find several lists over known defectors (wikipedia, Vladislav Krasnov's book, Russian History Encyclopedia).
I also found two documentaries about Nureyev, one seemingly focusing mostly on his ballet carrier called "Rudolf Nureyev-A Documentary" and one more focused on his defection called "Nureyev: The Russian Years" (link to the latter). I have yet to find them as downloads or copies I can purchase, but maybe someone else is more lucky. This article was also interesting to me, even if it was more about why he felt he had to defect than how he defected.
This video is the first interview Mikhail Baryshnikov held after he defected in '74, and this is an interview he held in '85 about his defection as well as the film White Nights, which might be relevant (I'll know when I've seen it :P).
Last, but not least, I found this article about Anatoly Kuznetsov, an USSR writer who defected in London.