What potential pitfalls can arise when using IP bans in PHP scripts for user interactions like comments and ratings?

Potential pitfalls that can arise when using IP bans in PHP scripts for user interactions like comments and ratings include the risk of blocking legitimate users who share the same IP address (such as in a shared network or behind a proxy). To mitigate this risk, it is recommended to implement additional measures such as user authentication or captcha verification to accurately identify and block malicious users.

// Example code snippet implementing user authentication in addition to IP bans

// Check if user is authenticated before processing comment or rating
if(isset($_SESSION['user_id'])) {
    // Process comment or rating
} else {
    // Display error message or redirect to login page
    echo "You must be logged in to comment or rate.";
}