Not to backup motobodo or something, but nature of non fullface helmet, you still have chance of fasterner and helmut slipped out especially during impact. U try hear that apollo helmet, fasten it, then try to remove it by sliding it to the front. U still can do that.

Now try the same with fullface helmet, u need to pull upward to remove helmet so the belt will properly secured to your chin.

Tldr: wear fullface helmet.