What are common issues and best practices when managing guest user data in PHP sessions?

Issue: One common issue when managing guest user data in PHP sessions is ensuring that the data is securely stored and accessed. To address this, it is best practice to sanitize and validate any input data from guest users before storing it in session variables.

// Sanitize and validate guest user data before storing in session
if(isset($_POST['guest_data'])){
    $guest_data = filter_var($_POST['guest_data'], FILTER_SANITIZE_STRING);
    $_SESSION['guest_data'] = $guest_data;
}