Deferred service provider overloading other deferred provider objects

gistfile1.php

class ValidationServiceProvider extends ServiceProvider
{
    /**
     * Indicates if loading of the provider is deferred.
     *
     * @var bool
     */
    protected $defer = true;

    public function register()
    {
        $closure = function() {
            $this->app['validator']->setPresenceVerifier(new DoctrinePresenceVerifier);
        };

        $closure->bindTo($this);

        $this->app['events']->listen('Illuminate\Validation\ValidationServiceProvider', $closure);
    }
}