Identify the unfair aspect with respect to the sentence extracted from an online Terms of Service:
```
hosts are not allowed to ask for a security deposit after a booking has been confirmed or outside of the airbnb platform . 

```
. OPTIONS: ["Limitation of liability", "Arbitration", "Unilateral change", "Unilateral termination", "Contract by using", "None", "Content removal", "Choice of law", "Jurisdiction"].