First lets put things straight. Indian companies threaten employees under the name of "blacklisting" them, so that they cannot get a job in the future. However, you leave a company, short notice, absconding, insubordination, whatever, the employer CANNOT blacklist you from future employment.
If the employee finds out that a particular employer is preventing an employee from future employment, he can sue the employer for an ungodly sum of money in court and WIN!! The employer will have to go to the streets.
So, don't ever, ever think about blacklisting an employee. Things don't work that way, what you see as unfair, will not be unfair to everybody. If an employee disappears, absconds from your organization, think about what you can do to decrease attrition rates, instead of taking unlawful shortcuts. That is the correct route.
Please don't get caught in a class action lawsuit. It will be very detrimental to the company, to your life, since the chairman will first rip you - the HR, apart, and the 1000s of employees working under it.
31st March 2010 From United States, Minneapolis