How can PHP developers ensure that their scripts for form filling do not violate spamming regulations or ethical guidelines?

To ensure that PHP scripts for form filling do not violate spamming regulations or ethical guidelines, developers can implement measures such as adding CAPTCHA verification, setting limits on the number of submissions from a single IP address, and implementing form validation to prevent automated submissions.

// Example PHP code snippet implementing CAPTCHA verification for form submission
if ($_SERVER["REQUEST_METHOD"] == "POST") {
    $captcha = $_POST['captcha'];
    
    // Verify CAPTCHA code
    if ($captcha != $_SESSION['captcha']) {
        echo "CAPTCHA verification failed. Please try again.";
    } else {
        // Process form submission
        // Add code to handle form data here
    }
}