Is it necessary to include error messages for missing checkbox selections in PHP form validation?

It is not necessary to include error messages for missing checkbox selections in PHP form validation unless it is a required field. If the checkbox is optional, you can simply check if it is set before processing the form data. However, if the checkbox is required, you can include an error message to prompt the user to select an option.

if(isset($_POST['checkbox_name'])) {
    // Checkbox is selected, process the form data
} else {
    // Checkbox is not selected, display an error message
    $error_message = "Please select an option for the checkbox.";
}