Vee Dee, the students in question were (or appeared to be) all well over 18, more like 20/21; they had an older bloke with them who was a sort of "group leader", and with whom the hotel were liaising. Unfortunately, since I do not speak Italian, and his English was very poor (perhaps conveniently?) I have no idea what his proper role was in all this.
Like Trev, I am sure that Island Hotels did all they were required to do in law, 'cos they're that kind of company. I do, however, admit to scant sympathy for the students - I know my daughter would get short shrift from me were she to be "disciplined" in such a manner! Then again, she has been taught respect for others