Identify the unfair aspect with respect to the sentence extracted from an online Terms of Service:
```
tripadvisor and some of its affiliates act as marketplaces to allow travelers to enter into vacation rental agreements or rental transactions with property owners and managers ( each , an `` advertiser '' ) . 

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