Just don't get your point here Gilly. The planning is done by the teachers, a/ for the trip itself and b/ preparing work for each and every lesson whilst they are absent- and discussing it with the person left in charge in their department or year- to ensure the work is understood and will go ahead as planned for the children left behind.
Mind you, I have to say I love the way they do it here, and in FRance too- where every trip involves THE WHOLE class, and not just those whose parents allow it or can afford it. Partly though fundraising, partly through subsidies for those who are on benefits, etc.
Our Welfare State. Is it broken?
Forgetting where you left your keys does not mean you are “losing it”