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