But only if she also accepts that if her children's teacher has children in the same situation then it would be OK for her to swan off to Ibiza as well
I disagree personally. As an adult I make the choice to work in a profession which places restrictions on when I can go on holiday. The other is a child, and for more people school is not an option - most have to use the state school education system. Home schooling, independent schooling and other systems are not actually easily open to all, many factors stand in their way especially financial ones.
Its irrelevant whether they went abroad or in the UK, if they stayed in a tent or in a 5* all inclusive hotel.
The bottom line is, it really doesn't make that much difference, if at all, to the vast majority of children (or their teachers) in my experience to miss 1-2 weeks of school.
Just don't expect the teachers to set and mark work.
Don't expect to get lots of catch up time.
Don't whinge about it, on/in the national media.
Do expect to help your own child catch up afterwards.
And these days, do expect to pay a fine - you will still save money on most holidays even with the fine included.