At the start-of-term feast in Chapter Twelve of Goblet of Fire Dumbledore announces the following:
“The heads of Beauxbatons and Durmstrang will be arriving with their short-listed contenders in October, and the selection of the three champions will take place at Halloween.
Shortly thereafter he says:
Only students who are of age — that is to say, seventeen years or older — will be allowed to put forward their names for consideration.
In discussing how the delegations would arrive in Chapter Fifteen, Ron says the following:
“A Portkey?” Ron suggested. “Or they could Apparate — maybe you’re allowed to do it under seventeen wherever they come from?”
Was there any reason to suspect that any of the visitors would be younger than 17? Dumbledore had said that the contenders are coming, and the contenders have to be 17. Was this just typical Ron nonsense, or were there actually some younger students that were supposed to be coming as well?