Today, I did not reset my Garmin 910XT before the run. Consequently today's run was totaled with yesterday's. The reason I didn't reset was that the reset notice was overwritten by the notice that my heart rate monitor was communicating with the watch.
Now think about this. Which notice is more important, and which notice should take precedence? I already know I'm wearing a heart rate monitor, since I put it on. Moreover, the watch has never once failed to receive the heartbeat signals, and if a really wanted to make sure, I could simply switch to the heart rate display on the watch. So that notice is, well, not particularly important.
But it is important for tracking my daily activity that one day's exercise not be totaled with another day's. So shouldn't that notice take priority. The watch should notify that a reset is needed in preference to heart rate signal reception.
I think this is something Garmin should fix by re-writing the 910XT software.