Identify the unfair aspect with respect to the sentence extracted from an online Terms of Service:
```
tripadvisor accepts no liability for travelers who are refused entry onto a flight or into any country because of the traveler 's failure to carry the travel documents required by any airline , authority , or country , including countries the traveler may just be passing through en route to his or her destination . 

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