Question on stiff arms

[swampcougar1]

You often see a stiff arm by ball carrier go into face mask of defender. Why is this rarely if ever called

 

[Empirical Cane]

You often see a stiff arm by ball carrier go into face mask of defender. Why is this rarely if ever called

A mystery along with RBs "targeting" defenders with their helmets as well.

 

[FuriousStyles]

You often see a stiff arm by ball carrier go into face mask of defender. Why is this rarely if ever called

As long as they don’t curl their fingers and/or pull them down the runner will get the benefit of the doubt.