Stupidity pretty much sums it up. If it wasnt for my £30 Giro Havoc i'd be dead now.. as fate would have it, it wouldnt have been on a DH track or even down the local trails, but doing my local 30 minute singletrack blast on my XC bike. I knew there was a branch hanging down but didnt duck enough.. hit it smack on at full pelt, snapped the clip holding the two straps together on my lid (the bit that clears your ears) with the impact and snapped the helmet clean in two. Luckily I only had bruising under the chin and mild concussion but it couldve been worse.. like your friend.