dabac

What I’ve seen happen though is a rider clamping down hard on the front brake, w/o being properly braced or positioned. Inertia then proceeds to drape the rider over the handlebar, at which point all semblance of balance and control is lost.
While not necessarily a lockup by definition, it can quite probably feel like one.
And blaming lockup, inferior design is more acceptable to the ego than admitting to user error.