I'm having trouble deciding whether to show a message in an app when the user presses the back button when exiting.
The following image shows how 9gag does this (see the message "Pressing Back to Exit" below).
I am worried that this may be annoying for some people, but I am aware that others may press the back button too many times and accidentally leave the page.
Can someone point me to research results or sources that cover this type of UX scenario?
I am interested in best practices in such situations.