Expired timestamp

I'm connecting to Drupal 7 through services and OAuth. All is working fine and I'm able to connect except in one situation:

When a client has a timestamp 10 minutes later (the server is working with punctual UTC+1).
The client tries to fetch token and the server refuses it with message "Unauthorized: Expired timestamp, yours 1341148133, ours 1341147701"

In OAuth.php: timestamp_threshold = 300 (5 minutes).
In function check_timestamp(), line 676 it takes time() (so it will get it in server timezone).

Any solution?
Also what will happens when client and server are in a different timezone?

For the moment the only solution is to avoid check_timestamp($timestamp) at line 648 in check_signature():

  /**
   * all-in-one function to check the signature on a request
   * should guess the signature method appropriately
   */
  private function check_signature($request, $consumer, $token) {
    // this should probably be in a different method
    $timestamp = $request instanceof OAuthRequest
        ? $request->get_parameter('oauth_timestamp')
        : NULL;
    $nonce = $request instanceof OAuthRequest
        ? $request->get_parameter('oauth_nonce')
        : NULL;
    //$this->check_timestamp($timestamp); // <-- TIMEZONE Errors!
    $this->check_nonce($consumer, $token, $nonce, $timestamp);

    $signature_method = $this->get_signature_method($request);

    $signature = $request->get_parameter('oauth_signature');
    $valid_sig = $signature_method->check_signature(
      $request,
      $consumer,
      $token,
      $signature
    );

    if (!$valid_sig) {
      throw new OAuthException("Invalid signature");
    }
  }

Which are the risks?

Thanks,
Miguel