Not unless it is new. I am a runkeeper elite member.
For those who do not think runkeeper or other phone apps will work asa long as you are on course...
Turn OFF the WiFi and 3G/4G antennas. The battery will last longer than the length of the marathon time limit, by a large margin. It's amazing how many folks do no know you can shut down some of these antennas.
If you are using RunKeeper Live for real time updates, however, only turn off wireless and NOT 3G/4G. It needs a data connection to keep updating the RunKeeper servers