For automatic Activity tracking (run, walk), it also auto-stops the activity when you stop moving. This is good.
When I manually start an activity (yoga, biking), I forget to stop it -- hours later, I glance at my watch & realize it is still recording since my yoga class hours ago. It would be a great feature (to have available, not everyone would want it turned on) that after 70min or 90min (user could set it) of an activity, the watch would alert/vibrate "Keep recording?" and the default would be yes (if I ignore it, because yes, I am biking up a hill right now, it should keep recording). Sort of like Pandora's little pop-up that says "Are you still listening?" Maybe I'm the only person this happens to, but I doubt it.
Thanks for considering,
Megan