Hide 15 miles of range, so it appears as zero, but the car can actually travel another 15 miles or so, similar to a low-fuel indicator in ICE cars.
Give an option to hide 15 miles or so from the user so that in an emergency they can “charge back up” to get an extra 15 miles. While this doesn’t actually add any more range and some people may just get into the habit of using it before hitting zero, it may help people psychologically be more careful and give people a second chance to get to a charging station.
Moderator: Really no need. The car warns you when your range gets low in several strong indicators. Tesla actually had a hidden reserve of 5-10 miles in early cars, but it was so rarely used/needed, they elected to show the real results all the time.