She sounds like a moron, but it doesn't sound like pictures, discussions of the consequences, etc will do anything, because she's in "won't happen to me" mode. I strongly advise you NOT to throw out her helmet. No matter how 'right' you are, I know I would react violently to someone throwing my stuff in the bin because they thought they knew what was best for me. That's seriously presumptious and condescending. Even though I agree with you 100%, don't go there. All you'll probably achieve is a pissed off friend, and perhaps theft charges if she's really pissed about it.
OTOH, there's nothing stopping you reporting her to the cops.
 It is against the law to wear a non-approved helmet, so dob her in.  Maybe continually getting pulled over and fined may make her change her mind.  Hitting people in the hip pocket often works when persuasion doesn't.
   It is against the law to wear a non-approved helmet, so dob her in.  Maybe continually getting pulled over and fined may make her change her mind.  Hitting people in the hip pocket often works when persuasion doesn't.




 
 



 
 



 (edit: meaning how cool they can look, not how nasty they look after an off)
 (edit: meaning how cool they can look, not how nasty they look after an off)


 
 

 Actually that sounds really good
  Actually that sounds really good   