If you have an iPhone SE Gen 3 (Or any other iPhone with TouchID, but models older than the SEGen3 have other weaknesses to worry about), you can do the same by spamming the power button 5 times.

You can also ask Siri to reboot or turn off your phone, Siri will ask you to confirm you want to do the action, but it doesn't take too long to do. Just in case you don't want to reach for your phone for what ever reason.

This is wrong. While this clears a some keys and prevents anyone from holding the phone up your face to unlock it, it doesn’t bring the phone back into a full BFU state.

Some keys can still be read, and depending on the exploit they use a lot of data could be extracted. BFU + good passcode is always the way to go.

> You actually don't have to power it down. If you hold the power and volume buttons for 2 seconds and reach the "slide to power off" screen, the phone is already hard locked. You then always have to enter the passcode to unlock it.

Iphones have 2 states when it comes to encryption:

Before First Unlock (BFU) - everything is encrypted. The most difficult state to hack.

After First Unlock (AFU) - data isn’t fully encrypted. Maybe it's for performance reasons. In this state exploits exist which police can use to get data.

Your suggestion of getting to the 'slide to power off' screen does NOT hardlock the phone (it does not put it in BFU).

It just means it requires a passcode. However, since it is in AFU mode, data can be exfiltrated with the right tools.

You should definitely power it down to be secure.

Any time a police encounter starts, you can at least tap the standby button 5 times. It's not as good as a shutdown, but it will at least disable biometrics so it will require a password to unlock. They can't legally force you to reveal your password.