i used to wonder how dangeroeus it could be too but after years of winter riding ive only had a little scathing of my pants. i mean there definetly is potential but falling off the bike has never produced any serious injury amoung any of my friends, you just fall in the snow! its actually alot less painful
id say moving the bike or loading the bike is more dangerous because your hands occasionally get scuffed up but thats about it.