Identify the unfair aspect with respect to the sentence extracted from an online Terms of Service:
```
we may update or revise these warnings and instructions , so please review them periodically . 

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