But it’s a bit like when you use an accountant to do your tax return - HMRC make it very clear that any mistakes are your responsibility and not that of any agent you have used.
I think she was very foolish to assume it would all be taken care of, especially given Labour’s promise of honesty and integrity.
Yes, it might have been an inadvertent error, but she should have been aware of her position and how important things like this are to the Daily Mail et al.