Personally I would never do such a thing, unless the company is really, really bad and this would be some sort of vengeance.
in reply to Bad conscience
People that do this are basically blackmailing their own employer. And you only have the leverage until you're replaced by a Perl script as the proverb says.
I see there's plenty of jobs in your country (I'm currently looking for employment myself in that same country). So, try another job, or try to have the upper-hand in your company by generating good business ideas and plans.
(At least, that's what I did at my previous company. Unfortunately, I got laid off during the cost-reducing phase they've had every few months. But my Perl code there is still running and doing good from what I see.)