An emergency SOS can be activated after quickly pressing the side button 5 times or after detecting a hard fall. You can adjust these on your watch under Settings>Safety and emergency.
The 5 presses cannot be changed. You can't even turn off the emergency SOS setting. The only thing you can turn off is fall detect. There have been random instances for some where the accelerometer for some reason detected a hard fall while users were asleep.
Indeed. Aside from disabling hard fall detection, I've found that setting a custom non-emergency number or turning on "Require swipe to call" may alleviate some of the annoyance of accidentally dialing 911 in the middle of the night.
