Identify the unfair aspect with respect to the sentence extracted from an online Terms of Service:
```
when a child under the age of thirteen ( 13 ) contacts linden lab , for example , to participate in a contest or to ask a question , we may collect that child 's email address and the e-mail address of the child 's parent or guardian . 

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