a CGMS can certainly help improve your control, but it's true there are more important things in life than having a perfect BGL. i am curious though, your parents check your BGL for you?('To be honest I think they just don't like taking my blood sugar.') how old are you? if you do it yourself would your parents let you not wear the sensor?
unless you are unwilling to check your BGL via a finger prick, then no, i don't think they can legally force you to wear a CGMS. anyway, i'm sure you already realise this, but CGMS technology isn't yet accurate enough to eliminate the use of a glucometer, you still have to check via a finger prick before bolusing, to treat lows, and to calibrate the sensor. so if you were unwilling to check your BGL manually, CGMS would be a waste of time anyway.
i can't see you ever being legally forced to go through the pain and bodily harm of wearing a CGMS unless you can't control your BGL well enough to keep your HbA1c under 8 or 9% (yes, i realise that is not in the 'target' range, but kids have got to be allowed to be kids), AND have exhausted every other control technique available to you, eg pump, different types of insulin, exercise, diet etc.
like i said though, personally i think that CGMS is a extremely useful tool, and worth the pain and awkwardness, and not because i'm a control freak either, just because it makes life so dang well easier.
*NOTE*: to all those who have answered saying that yes, legally a parent can make such decisions in regards to a child's health, should realise that a childs welfare concerns both their psychical AND MENTAL health. There is no denying it, inserting CGMS sensors hurts, and as correctly stated by OCD are not 'necessary' for good diabetes management.
type 1 diabetic