Its a never say never kind of thing. Of course a protector will help if something hits it, but will something hit it. I seem to have done most of my off road on stoney long lanes.. as well as plenty of boggy areas getting roosted to death, on KTM Exc's, DRZs... all the guys Ive ridden wth have also had bikes with rads of much the same make. Have I ever been out and had a holed rad..... the answer is no.Ive had stones hit my body... jeez they hurt on the knee cap!!! If it does happen then it can ruin your day for sure, but so will bent handlebars, or snapped risers... Ive seen more of this than anything. I rekon sometimes we get overly paranoid about what we need to bolt onto the bike, to make it safe to go off the beaten track