Teacher unions are under fire for forbidding principals work for even 30 minutes at the start of next Tuesday's one-day strike to ensure the safety of any pupil who turns up for school.
For the first time in such a situation, unions are not giving a derogation to principals/deputy principals to carry out essential duties when more than 700 schools close.
With less than a week to go, schools are advising parents that they should not send their children to school, but a leading school management body said it was possible that some parents may choose to do so.
Michael Moriarty, general secretary of Education and Training Boards Ireland (ETBI), said there was a danger that some pupils would turn up, adding "some parents might want to register a protest by doing that".
He said it was unprecedented that, as a goodwill gesture, there was no facility for principals to open and close, to enable them to fulfil their contractual obligations, including ensuring the safety of their pupils.
The two second-level teacher unions are also under pressure from a groundswell of principals and deputy principals voicing concerns about the decisions to go ahead with the strike, particularly in light of the compromise tabled by Education Minister Jan O'Sullivan.
Growing numbers of principals and deputy principals are going public with their views that the proposed reforms, which including teachers assessing their own students, must go ahead because the changes will be good for pupils.
Among them is Sr Liz Smyth, vice-principal of St Dominic's Secondary School, Ballyfermot, Dublin, who rejected union arguments that teachers assessing their own students would lead to inconsistencies, inequity and lower standards. "We have all had the same training," she said.
The Association of Secondary Teachers' Ireland and the Teachers' Union of Ireland have rejected a call from Ms O'Sullivan to call off the strike.
The unions are opposed mainly to teachers taking over any responsibility for assessing students, as part of a wider move to end reliance on the traditional Junior Cert exams and the rote learning they encourage.
The original proposal was that teachers take over full responsibility for grading their own students, but Ms O'Sulllivan has proposed reducing that to 40pc, with traditional exams accounting for the other 60pc.