Unless there is GOD, nothing is omnipotent.

Fairness in work place and strong technical/personal skills are the prerequisite for the above mentioned method to work. If the boss only wants to get free labor, you will be exploited to the limit. If your caliber is sub par, the position will be filled by a more capable person. You can use this technique to knock on doors. But to live in the house, you have to bring something unique to the table.