It all comes down to a fundamental question: What happens when a detached electric field hits a charged object? If an electrostatic interaction occurs between the field and the object, then this device should work.
We know that two charged objects exert a pair of forces (equal and opposite) on
each other. I would hypothesize that a charged object and a detached field cannot exert a pair of forces (equal and opposite) on each other, because the detached field is not anchored to anything but empty space.
To demonstrate this, we start with two charged objects, A and B, seperated by a rigid beam. This beam-assembly is floating on a frictionless surface. The two charged objects are exerting a pair of forces on each other (they are either attracting or repelling each other).
Next, we turn off the charge at A, and the detached field will either propagate toward B for some time (based on the speed of light, for example), or it will disappear instantaneously. Since the beam assembly does not lurch in either direction, we surmise that the electric field must have collapsed instantaneously.
We further surmise that all fields (electric, magnetic, gravitational...) collapse instantaneously.
We do not surmise that all fields are
formed instantaneously. The field could have formed by propagating outward at c in all directions, and we could still have the same results.
(My 2 cents).