I've had one over for supper! When my ex and I had exchange students, we had a boy from Belgium whose parents were doctors, he was pretty well full of himself, but in a likeable way. I used to say that Ben could mooch off you in such a way that you wished you had more to give him, that's how charming he was.
Anyway, he befriended a fellow exchange student from Belgrade, who had a horrible experience with his host family. The young man had to do a lot of the work around the house, the family life was a wreck (pregnant 20 year old unmarried daughter in the house), and to top it off, he often had to buy his own food! Needless to say, when he had a chance to have dinner with us, he jumped at it.
After the Belgian boy left, we were approached by the Serbian lad's visit co-ordinator, who ascertained that this young man was not the problem, his host family was. We took him for the last four months of his stay in the US, and turned the whole trip around for him. Of course, he was delighted to find that a lot of Americans (and believe me, we introduced him to them) didn't like Clinton!
Truly, one of the best experiences of my life.
Great story about your Serbian guest ... and a great service, introducing foreign students to *conservative* Americans!