Take our survey and get a $50 gift card! It's a common request that I receive. I get quite a few requests to complete surveys or to participate in a focus group discussions. The exchange is always the same - a bit of information for a small incentive. If you arrived here hoping that I would participate, save your time. I almost never participate in these. It's not that I dislike sharing info. I'm just avoiding potential future issues.
In my role, I am frequently comparing various services, and I often make requests for specific information about capabilities or pricing. My goal is to find a product that meets my needs at a price that meets my budget. If you follow up my information request with the survey/gift-card response, the email will go straight to the trash. I will not do anything intentionally that creates a perception that my future product decision was influenced by a gift card or some other offering.
If you want feedback, just ask for feedback. Is my take on this completely wrong? Let me know.