Typically the employee's father (or some similarly close relative) will sign a legal agreement with the employer promising to pay back the employee's wages if the employee disappears. (Legally I believe this is similar to a guarantor for a bank loan.)

Though this probably won't stand up in court, most employees wouldn't risk putting their own father through the trouble of finding out.

Ha, this isn't even as severe as what goes on. Some companies ask to pay upto 75% of their annual salary as a security deposit (refundable on quitting with some T&C).