Those who are effectively saying “it’s been and gone so tough luck you don’t get to talk to your child’s teacher this year” (and yes I understand that is probably the legal position) - are you ok with the postal unions just burning that day’s mail if there’s a postal strike or do you expect it to be delivered later? If you have an operation cancelled because of a nurse’s strike are you ok with being told your hip replacement or cancer surgery is gone forever or would you expect it to be rearranged?
(OP I think in your circumstances it’s entirely reasonable to not attend.)
I agree completely with this. It's thoroughly reasonable for OP to say that she has a commitment on evening X, but could do evening Y or Z - especially as she wasn't on strike the original evening; but then the strikes will impact fellow staff just as they impact parents and children.
However, anybody saying that a significant once-in-a-year event can't ever go ahead, because the unions called a strike on the original day, is being plain nasty. Strikes are meant to be disruptive to the job in hand, but not to prevent vital parts of it from ever being done. The only sensible solution is that the essential things are rearranged to another day at the expense of 'nice to have' things whose place in the timetable they then take.
How would the teachers feel if the people who ran their payroll went on strike for whatever reason on the day of the payment run - and the results weren't just that they were paid a day or two late (difficult to have to deal with, but within the bounds of the disruptive intentions of a strike), but that they would never be paid at all for that month - because to process the month's payroll at any time would 'not be in the spirit of the strike'?
Unfortunately, I think that, once you start claiming that key parts of your job can just be scrapped and never done at all, all you're doing is weakening your hand as to the outside perception of how important your job actually is in the first place.