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 . 

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