See, I think I did it the better way: bought a nighthawk at 19 years old without asking my parents, learned behind their backs (at 1am...in the rain...), then moved out soon after and told them not to give me any money. They kinda freaked out on me, although that was also due to me getting a girlfriend who was 9 years older with lots of tats etc.....hmm, maybe they
weren't all the best decisions I've made.....

(although I would spring for a bad decision again if it involves a hot woman with tats any day...but no kid next time!)
I think my first bike might still be chained up, but that's why I bought a new one where I live now.

....I just have to tell em about it sooner or later.
Seriously, if you can, moving out is a great thing to do, and the fact that more and more kids aren't doing so is and will be a negative aspect of our society. Motorcycling is dangerous. If I had kids, I would not let them ride, unless I felt they had an outstanding maturity (but then they'd be related to me...). It sounds messed up, but try to understand their fears, and be reasonable as you can knowing that the roof rule and dependency rule is just that...rule.