A huddle of teenagers in pyjamas was arguing vociferously a little way along the path. When they saw Harry, Ron and Hermione, a girl with thick, curly hair turned and said quickly, "Ou est Madame Maxime? Nous l'avons perdue -"
(Goblet of Fire, Chapter 9, The Dark Mark)
These students are confirmed by Hermione to be pupils at Beauxbatons. They're asking where Madame Maxime is. It seems strange to me that they would expect to find their Headmistress at a sporting event in the middle of the summer. Hogwarts students don't ever see their teachers during the holidays, although Harry does speculate about where Dumbledore might go.
As for informing the Headmaster, Harry had no idea where Dumbledore went during the summer holidays. He amused himself for a moment, picturing Dumbledore, with his long silver beard, full-length wizard's robes and pointed hat, stretched out on a beach somewhere, rubbing suntan lotion into his long crooked nose.
(Goblet of Fire, Chapter 2, The Scar)
Why would the Beauxbatons students expect to find Madame Maxime wandering around in the middle of the woods at the Quidditch World Cup?