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