webstandardcss on "Why will mobile users be redirected to the splash when i'm trying to exclude the"

Why will mobile users be redirected to the splash when i'm trying to exclude them from viewing this page. I just want desktop users to use be redirected to this splash and not the mobile users.

/*-------------------------------------------------------------------------------------*/
    /* Splash Page Hooks and Filters
    /*-------------------------------------------------------------------------------------*/

    // Get the user agent strings.
    $ipod = stripos($_SERVER['HTTP_USER_AGENT'],"iPod");
    $iphone = stripos($_SERVER['HTTP_USER_AGENT'],"iPhone");
    $ipad = stripos($_SERVER['HTTP_USER_AGENT'],"iPad");
    $android = stripos($_SERVER['HTTP_USER_AGENT'],"android");
    $windowsphone = stripos($_SERVER['HTTP_USER_AGENT'],"IEMobile");
    if( ! function_exists( 'custom_splash' ) )  {
        function custom_splash( $username ) {
            $referrer = $_SERVER['HTTP_REFERER']; // where did the user come from?
    	// If not mobile user.
    	if ($ipod == false || $iphone == false || $ipad == false || $android == false || $windowsphone == false) {
    	        // if there's a valid referrer
    		if ( empty($referrer) && ( is_front_page() || is_home() ) ) {
    			wp_redirect( '/splash/' ); // Redirect to the splash page.
    		}
    	} else {
    	}

    	return $referrer;
        }
    }

    add_action( 'wp_footer', 'custom_splash' ); // hook splash page