Identify the unfair aspect with respect to the sentence extracted from an online Terms of Service:
```
if you engage in any exercise program you receive or learn about through the fitbit service , you agree that you do so at your own risk and are voluntarily participating in these activities . 

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