Dear Jharna,
Greetings!!
Since you are in a profession which is a job of great responsibility, I understand and appreciate the criticality of the situation.
You have to make the employess understand that the notice period that any employee is serving, is not meant to make money for the company. It actually stands for the time needed for the organization to hire a new person in his/her place and train the new person for that job. It is to ensure that the continuity of the work remains and the project which the employee was working on does not get affected just because the employee has picked up another job.
Also, a company which is employing thousands of people and paying their salaries every month does make great money in case it is not paying just one of its employess for a mere 15 days. Only then will the employees understand the importance and the relevance of their job and the notice period served.
Any employee saying such a thing is just trying to misguide you and get his payment done!
I hope that this info helps you...
Best Regards,
Ag