United is now letting you use your cell phones a few minutes earlier on landing. This is probably only useful to call ahead to the valet so that your car might be ready when you arrive.
CELL PHONE USE ALLOWED AFTER LANDING
Beginning today, you may use cell phones* shortly after landing on all domestic United flights after the aircraft has left the active runway and is taxiing toward the gate. Flight attendants will make an announcement advising you when it's safe to use your phone. For safety reasons, you will not be allowed to leave your seat during taxi to retrieve your phone.
On departure, you may use cell phones on domestic and international flights only when the aircraft door is open. Two-way radios are not allowed for use anytime aboard the plane.
*Cell phone must be approved and licensed by the United States Federal Communication Commission (FCC).