Oooh, I never thought the forum would go nuclear over this one
I always saw it coming down to a debate over whether "have a go heros" should be allowed to carry AK47s or something.
As another tree hugging, left wing, Guardian reader (although I dropped out of my yoghurt weaving degree because it was secretly run by
The Corporations man!) I'm suprising myself by leaning toward the "stick to the rules" camp.
Firstly, arguments to use against the school, because I can certainly see validity in the argument, obviously on a personal level, and quite likely on a wider level too.
1. I'm guessing no-one at the school is going to be arguing that your sister is predicted to get better than the school average grades - do they really want to kick out someone who's going to pull up the school's grade point average?
2. By explaining what your sister is going to be doing with the "free" time that can't be accomplished at school you both prove to the school that by allowing flexibility she'll acheive better results and consequently pull the school up the league tables and secondly will give the school some pointers on what they need to improve.
However, I said I'm leaning toward the "stick to the rules" camp. The rules in place will have a reason, it might not necessarily be a reason that is valid at a personal level but may make some sense when applied to the smooth running of an entire community, ie a school.
One that I can think of off the top of my head would be fire safety - I'm guessing the school needs to keep track of who's in and out of the premises at any given time in case the physics lab goes thermo nuclear or something. Now sure, that can be negated by just agreeing that your sister signs in and out when she comes and goes, however when that's applied to a whole sixth form the school will likely need to pay some admin person an extra hour a day to keep track of it all - that's money that could be better spent on.... better facilities.
The school could be trying (apparently failing admittedly, but trying) to create a "community". You see this more in private schooling and religious state schools, you'll find that certain activities (even past 16) that have no practical bearing on your ability to pass exams will still be compulsory. This is all geared to producing rounded individuals rather than just exam passers. Now admittedly, if this is their goal then it sounds like they're failing, but in the school's shoes - if they allow opt outs of this (and bear in mind once one is allowed then a precedent is set) then the whole school community attempt (at sixth form level at least) is effectively abandoned - they might not want to abandon this concept just yet.
Challenge rules, definitely always challenge rules - in fact that's part of what the school will likely be teaching - make sure the reasons for them are still present and at least in some way valid rather than just a blind adherence to "that's what we've always done". If there is a valid reason consider if whilst it might not be personally applicable it makes some sense in the context of managing and improving an entire community.