There is an advert making the rounds in the UK, which shows the dangers of wearing a seatbelt. If you hit something, your body stops, but your internal organs keep moving forward, and slam into your ribcage (or whatever). If you don't wear a seatbelt, you have more time to slow down before your body actually stops, so the UKs "wear a seatbelt" campaign has made me think twice about putting one on.