Identify the unfair aspect with respect to the sentence extracted from an online Terms of Service:
```
6.3 you are responsible for paying any service fees that you owe to airbnb . 

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