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