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How Do I Prepare My Phone for a Protest?
(themarkup.org)
This is a most excellent place for technology news and articles.
I learned this recently: if you have an iPhone, pressing the lock button five times rapidly will lock it so that you need to enter a passcode, not just FaceID. Useful if you think somebody might forcibly use your face to unlock it
Yes, but this will also call emergency services after, I think, ten seconds.
Make sure you cancel that call right away unless you actually need them.
Honestly, it would be kind of funny that your phone calls emergency services when you get pulled over and you don't want them to force you to unlock your phone, having a 911 operator recording the entire interaction's audio.