I was wondering same thing and found this in emails when claiming a power user item: (hope it helps)
"We would like to inform you of some changes to our Power User Program:
Regarding Amazon’s new rules
We comply with Amazon regulations against incentivized reviews. We do not require you to write a product review on Amazon, and whether or not you decide to do so will have no impact on your eligibility for product samples.
To prevent Amazon from blocking your account, or prohibiting you from writing reviews in the future, please don’t includes words like “free product in exchange for review” if you choose to write an Amazon review.
How to share your experience
For the sample you are testing or will receive to test in the future, we expect you to post your product experience online. Whether it’s a social media post, YouTube review, forum contribution, or a detailed side by side comparison, we hope that sharing your experience will help other customers make more informed decisions and enhance Anker's visibility.
Tell us about your experience
Please be aware that submitting your review link on the Anker Power User page is unnecessary. Instead, when your review is finished, please email your review link to email@example.com, and we’ll update your status accordingly. We are currently in the process of upgrading our page and you will be able to submit your review link on our website soon.
Experienced a problem with your sample product?
If you have any questions or suggestions regarding our products, please get in touch with us at your earliest convenience. We are always excited to work with our customers toward improving our products.
Thanks for your understanding and support!"