I have used my I phone for years as a wake up call. Never had a problem, it seems much easier than trying to learn a clock in a strange hotel room and easier than messing with the front desk too. Last year I was in impound and had to be out early to be out of impound by 7:00. Set my alarm for 5:00am and was fine. Got up the next morning, took a shower and glanced at the clock in the room and it said 6:20! Holy crap, got dressed and flew out the door towards the track. Got the bike loaded and headed to the gate at 7:05. They said no and someone else in the class set the record 5 mph faster than I could ever run again.
The lesson was that the I phone is pretty smart and even though all of Wendover uses Mountain time, Apple in its wisdom went back and forth from Mountain to Pacific time and woke me at 5 Pacific time instead of 5 Mountain time. Lesson learned. Hopefully this year I will have more horsepower AND a reliable clock!