Identify the unfair aspect with respect to the sentence extracted from an online Terms of Service:
```
8.1.3 if you book a host service on behalf of additional guests , you are required to ensure that every additional guest meets any requirements set by the host , and is made aware of and agrees to these terms and any terms and conditions , rules and restrictions set by the host . 

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