A lot of Android apps use the only alert once flag to update the content of an existing notification without causing any interruption.
Unfortunately, it seems Garmin Connect does not transmit this flag to the watch since every update make my Forerunner 935 vibrate, which is extremely annoying for often updating content such as live score updates from Google Now.
I also believe there should be a way to prevent the watch from vibrating if the notification priority (old API) or importance level (new API) is set below a given threshold. The notification would still be available on the watch, but wouldn't interrupt or vibrate depending on the level.
In Notification settings, Google defines the following importance levels:
- Low: No sound or visual interruption. The watch should just add the notification to the list without any peek or vibration
- Medium: No sound. The watch could show a peek of the notification but shouldn't vibrate.
- High: Make sound / Urgent: make sound and pop on screen. The watch should show a peek of the notification and vibrate.