We received such letters from a family we knew at one time, jest not Laura they were practically as bad as your spoof outline. They got worse year on year, the list of children's achievements got longer, they were self sufficient from what they grew in their garden where the matriarch of the family as well as working spent spare hours toiling. The children as well as achieving academically were all musically gifted and enthusiastically embraced going round museums and art galleries on summer holidays, this was during their teenage years No mono syllabic grunts from these wonder kids, something we as parents expected from our own progeny, shuffling along and moaning and groaning if there wasn't a ride to be had. In fact if we did visit anywhere cultural ours went into serious bargaining negotiations along the lines of "I'll shut up about how boring this is if you buy me something I want" When one of my children was at his absolute worst, teenager from hell and beyond, we would get comments in their letters along the lines of "our children continue to make us very proud parents" the sick bag really needed to be adjacent whilst reading such drivel boastful snippets. Some years later we did find out at least one of the children, had a bit of a secret life, suffice to say it didn't fit in with the rosy picture they painted. These letters got so annoying at one stage, I have to confess I took to reading them out to Christmas/New Year guests, said guests having practically fallen off chairs in hysterics, once they'd picked themselves off the floor, thereafter clamoured to hear the "Round Robin" during their visits.
Then one year, we got a snippy note in card from the proud patriarch along the lines of "I gather from some (not us) that Round Robins aren't really appreciated. Someone obviously upset him