Aaron's registration script

<?php

class register {

    public static function createAccount($data, $conn)  {

        $birthday = "1990-01-01";
        $ipaddr = $_SERVER['REMOTE_ADDR'];
        $username = $data['musername'];
        $password = sha1($data['mpass']);
        $email = $data['memail'];
        $tempban = '1970-01-01 12:50:00';

        if (self::validate($data, $conn))   {

            echo '<div class="alert alert-success">You have succesfully registered!</div>';

            $stmt = $conn->prepare("INSERT INTO accounts (`name`, `password`, `ip`, `email`, `birthday`, `tempban`) VALUES (?, ?, ?, ?, ?, ?)");
            $stmt->bind_param("ssssss", $username, $password, $ipaddr, $email, $birthday, $tempban);
            $stmt->execute();

        }

    }

    public static function validate($data, $conn)   {

        if (!self::inputValidation($data["musername"], "username")) {

            self::throwMessage(6);
            return false;

        }

        if (!self::inputValidation($data['memail'], "email"))   {

            self::throwMessage(3);
            return false;

        }

        if (!self::inputValidation($data['mpass'], "password")) {

            self::throwMessage(5);
            return false;

        }

        if ($data['mpass'] != $data['mpwcheck'])    {

            self::throwMessage(4);
            return false;

        }

        if (!self::checkAvailability($data, $conn)) {

            self::throwMessage(2);
            return false;

        }



        return true;

    }

    public static function inputValidation($object, $code)  {

        switch($code)   {

            case "username":
                if ((strlen($object) > 4) && (strlen($object) <= 12))   {

                    return true;

                }
                break;

            case "email":
                if (strlen($object) >= 1)   {

                    if (filter_var($object, FILTER_VALIDATE_EMAIL)) {

                        return true;

                    } else {

                        return false;

                    }

                } else {

                    return false;

                }
                break;

            case "password":
                if (strlen($object) >= 6 && (strlen($object) <= 30))    {

                    return true;

                } else {

                    return false;

                }
                break;

            default:

                self::throwMessage("WRONG");

                break;

        }

    }

    public static function checkAvailability($data, $conn)  {

        $result1 = 0;
        $result2 = 0;

        $username = $data['musername'];
        $email = $data['memail'];

        $user = $conn->prepare("SELECT * FROM accounts WHERE name = ?");
        $user->bind_param("s", $username);
        $user->execute();
        $user->store_result();

        if ($user->num_rows() > 0)  {

            $result1 = 1;

        }

        $email = $conn->prepare("SELECT * from accounts WHERE email = ?");
        $email->bind_param("s", $email);
        $user->execute();
        $user->store_result();

        if ($email->num_rows() > 0) {

            $result2 = 1;

        }

        $results = $result1 + $result2;

        if ($results > 0)   {

            return false;

        } else {

            return true;

        }

    }

    public static function throwMessage($code)  {

        switch($code)   {

            case 1:
                echo '<div class="alert alert-success">You have succesfully registered!</div>';
                break;

            case 2:
                echo '<div class="alert alert-danger">The entered username or e-mail adress is already taken.</div>';
                break;

            case 3:
                echo '<div class="alert alert-danger">Your e-mail did not pass our validation.</div>';
                break;

            case 4:
                echo '<div class="alert alert-danger">Your passwords did not equal!</div>';
                break;

            case 5:
                echo '<div class="alert alert-danger">Your password did not pass our validation!</div>';
                break;

            case 6:
                echo '<div class="alert alert-danger">Your username did not pass our validation!</div>';
                break;

            default:
                echo '<div class="alert alert-danger">An unexpected error occured!</div>';
                break;

        }

    }

}