Inputs guaranteed at 60 fps

I was talking about making a fighting game in Unity, and this came up:

"You absolutely 1000% need to guarantee inputs are checked once every 60th of a second."

While drawing to the screen and what-not can be variable, I agree with this guy that inputs must happen at a consistent time, not when Unity feels like it. ("Unity can almost do that with FixedUpdate but it doesn't quite work how you want.")

Can anyone with more familiarity with Unity see a way around this?

Edit: I'm asking about making sure inputs are checked at a consistent time, not about avoiding missing inputs.

You can get all input events (except MouseMove) in real time using `OnGUI` hack:

public class SomeDummyClass : MonoBehaviour
{
    void OnGUI()
    {
        // ensures you get _every_ event
        GUI.depth = int.MinValue;
        YourCallback(UnityEvent.current);
    }
}

P.S. I think it's such a shame, that Unity hides raw events from programmers and force them to use polling.

P.S.S Little experiment (click with Mouse0 as quick as possible):

alt text

(grab code here)