hey won't fail/break unless unless put under extreme stress (i.e. you're a very heavy rider, slamming on the thing while going down a very steep hill

is this something i should be worried about! The SNG are cheaper I have them on my girlfriends bike are they going to explode if she brakes on a hill? shes not heavy but I dont want to her die/explode.
Or is this like 400lbs going 60 KPH sort of idea?