My views differ from that of Sahil.
Its similar to the notice pay issue.
When an employee leaves the company earlier than promised, then he has to pay some compensation to the company. Therefore, such an act is not covered as employer-empoyee relationship and since the payment is flowing from employee to employer the said activity would amount to refraining from being an employee of the company. Hence, such an act is taxable.
Same way, when the deposit is given, the same is covered by negative list, but since, in this case, when the tenant is refraining from staying in the room, then breaking the agreement is refraining from doing such an act. Therefore, this will be again taxable under Service Tax Law.
People may have different opinions, but I am pretty sure on this, you may refer the Act.