If the user just uses regen braking, they are never hitting their brake when they are moving. You would have to work it somehow into the regen, but the stopping curves are completely different for the two, so you would probably wind up surprising the driver if you decided to arbitrarily engage the brake rather than use regen.

Your assumption is that regen and braking have the same behavior and are interchangeable, but I don't think that's the case beyond both of them being used to stop.