Anyone who has ever passed their iPhone over to show a photo or video will probably recognise the instant dread that kicks in when the other person starts swiping somewhere they were never meant to go.
There is, however, a simple way to prevent that from happening, and a lot of people are only now discovering it.
The tool has been built into the iPhone for quite some time, and once you know where to find it, it becomes far easier to hand your device over without worrying about wandering fingers.
It is called Guided Access. While many people now use it to keep snoopers out of their phone, that was not its original purpose.
Apple introduced the feature as a kind of child lock, so parents could let children use the phone without opening the door to every app and setting on the device.
Over time, people worked out that it is just as useful when dealing with overly curious friends, partners or co-workers.
When it is enabled, Guided Access keeps the iPhone locked to one app only.
That means the person using your phone can view exactly what you intended to show them, without being able to jump into your messages, photos or anything else.
Getting it ready only takes a minute or two. Open Settings, tap Accessibility, then scroll until you see Guided Access and turn it on.
After that, you can choose how to end a session, either with Face ID, Touch ID or a passcode.
Whichever method you select will be the one needed to return the phone to normal use.
To start Guided Access, open the app you want to show, then triple-click the side button on iPhone with Face ID, or the Home button on older models. If you have added it to Control Centre, you can also start it from there, and Siri can be used as well.
Depending on the iPhone model, the shortcut icon appears as a padlock inside either a circle or a square, and it can look quite similar to the screen rotation lock symbol.
There are also extra controls available, such as blocking touch input in certain parts of the screen, turning off the volume buttons, disabling motion, or preventing the on-screen keyboard from appearing, although the basic setup is often enough to stop unwanted scrolling.
There is one major drawback to keep in mind. While Guided Access is running, Crash Detection and emergency services are not available, so it is best used temporarily when someone else is holding your phone, rather than left on for long periods.