Identify the unfair aspect with respect to the sentence extracted from an online Terms of Service:
```
the nintendo account service must not be used for any other purpose . 

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