I agree Mystery, I suspect that the schools / LEA get more interested if there are repeated absences - also if permission is given for 10 days and the kid doesn't reappear for a month for one reason or another.
(9) The following are prescribed as the grounds on which the name of a pupil of compulsory school age shall be deleted from the admission register:
(e) ..... the pupil has failed to attend the school within the 10 school days immediately following the expiry of the period for which such leave was granted, and the proprietor is not satisfied that the pupil is unable to attend the school by reason of sickness or any unavoidable cause.
I can't say how common this is in general, but I certainly used to hear some appeals where a school place had been withdrawn because the child's unauthorised absence had gone beyond 10 school days on a single
occasion. (These appeals were not strictly speaking against the withdrawal of a place as such, but rather an attempt by parents to try and get the pupil reinstated at an oversubscribed school, as the vacant place had been reallocated.)
I think the school ought first to initiate reasonable checks to try and ascertain the pupil’s whereabouts. Equally, it would be wise for parents to contact the school immediately if their return home is unavoidably delayed.