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