You took them to see the POPE.
😆
Sadly though from what youve put down you seem to have done everything by the book, perhaps too by the book and not allowed small things to go wrong.
Also from how i see it you got the kids outside as a group,enjoying the fresh air, with supervision, and just hopefully the bug will hit them and they in the future will want to get out more, and possibly in the future try to do the same for their children or students.
Sincere apologies for not being negative.
If the senior management want to argue mention redundancies of useless senior management who probably dont know one end of a kid from the next, and hopefully their name will be top of the list.