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' 'Jurisdiction' 'Contract by using'
 'Unilateral change' 'Unilateral termination' 'Choice of law' 'None'
 'Content removal' 'Arbitration'].