Hmmm, allow me to nitpick here but:
(b) hotel accommodation in cases
[1]- where a stay of one or more nights becomes necessary, or
[2]- where a stay additional to that intended by the passenger becomes necessary;
If [1] covers from 1 to X nights... then why is [2] necessary? Doesn't the very presence of [2] here imply a stay other than a stay of 1 to X nights. In other words, a day stay?