Why does my iPhone make calls to my emergency contacts on its own?

Question

Sometimes when carrying my iPhone X in my pocket, it starts making calls on its own. It calls the same person every time (my father).

The phone is configured as such:

1. Phone locked
2. Face ID activated
3. Emergency contacts are set up in Health app - my father is one of them, but there are a few others, both before and after him on the list
4. In Settings → Emergency SOS I have:
   Call with side button: Off and
   Call automatically: Off
5. "Today" screen: I do not have the Favorites widget or any other widget for making calls.

I have tried reproducing the problem by holding the right and top left side buttons pressed, but this only gives me the screen with a Swipe to turn off, Emergency info and Emergency SOS. No matter what I do, it does not just set up a call.

I read a Reddit post, where a user experiencing this problem when walking up stairs, describes how the problem is triggered:

After doing some experimentation, I think I figured it out.

If your iPhone is in your pocket and the screen is facing your body, the motion that your legs make when walking up a set of stairs "taps" the bottom left corner of the screen (at least for me).

the first tap registers as a swipe up, which, because FaceID is not recognizing a face (because it's in your pocket), goes to the passcode entry screen

2) the second tap clicks the Emergency text in the bottom left of the unlock screen

3) the third tap clicks the Medical ID text in the bottom left of the Emergency screen

4) the fourth tap clicks the phone number of the second emergency contact at the very bottom

These symptoms match pretty well with what I'm seeing. I have experimented with adding/removing/sorting emergency contacts, and it does seem like it is the second emergency contact, sometimes the first, that gets called.

Another user in the Reddit thread suggests a solution:

Go to Settings > Accessibility and turn off Tap to Wake

However, in my case, I've already disabled Tap to Wake.

What makes my phone want to call my father seemingly randomly, and what can I do to make it stop?

Answer 1

Following hints from the Reddit post:

If your iPhone is in your pocket and the screen is facing your body, the motion that your legs make when walking up a set of stairs "taps" the bottom left corner of the screen (at least for me).

the first tap registers as a swipe up, which, because FaceID is not recognizing a face (because it's in your pocket), goes to the passcode entry screen

2) the second tap clicks the Emergency text in the bottom left of the unlock screen

3) the third tap clicks the Medical ID text in the bottom left of the Emergency screen

4) the fourth tap clicks the phone number of the second emergency contact at the very bottom

... I found a solution that at in most cases prevents accidentally calling my emergency contacts:

1. Create a new contact called "Dummy" or similar, with an invalid phone number (e.g. 12345678). Make sure you have at least one other emergency contact.

2. Go to the Settings app → Health → Emergency info, and find the Emergency contacts list

3. Reorder your emergency contacts so that "Dummy" is number 2 from the top

This setup will cause your Dummy contact, and not a real contact, to be called when the bottom part of your screen is tapped in your pocket.