While it is fine for you to expect to provide adequate period for leaving an organisation, there are organisations that try to ensure that your next employer is not too hot about you coming in because of the hassles they put in. A FI in Mumbai with export import orientation even manages to extort money out of employees who are leaving and their top mgmt. calls the prospective employer bad mouthing the employee. No wonder many of its employees just walk out without saying anything. If the employee has a responsibility, what about the employer?