If not wrong, a few years ago once they started a server you can at least some reward. Around 5-15$ for the selected user who are filling the form, which mean only some people got the survey and not everyone.
If I remember it correctly, the marketing team of Stake had run a review campaign in 2019. They had asked the users to submit reviews on Trustpilot, then they rewarded the users for the review. I remember I had submitted review for both Primedice and Stake and received a small reward from them in both platforms. They didn't ask to post the positive feedback only.