Yes, should have mentioned that some time ago. It is a feature on subal models (for Nikon at least) that has been available for at least the last few models. Some other brands don't have this capacity. I get a blank look from the owners of other brands when I describe this technique. Not sure if it justifies the cost, but I use it as an explanation why I buy Subal.
To be clear, what I do is set the AF on continuous. I focus with the AF on button. When I then push the shutter button the camera fires regardless is the camera thinks the subject is in focus or not. Gives you an instant shot. You never have to wait for the camera.
Thanks for reminding folks of this technique.