The line between 'building a review strategy' and 'review manipulation' is stricter than most sellers assume.
Reviews make or break conversion rate on Amazon, which is exactly why so many sellers get tempted into gray-area tactics. Amazon treats review manipulation as one of the more serious policy violations.
Packaging inserts asking for reviews, review requests sent through outside email tools, and "review clubs" disguised as customer communities consistently get flagged. If a tactic requires disguising what you're doing, it's a violation with extra steps.
Check for a real pattern first, a batch of similar complaints is often useful product feedback, not an attack. If a defect has since been fixed, respond publicly and factually.
If you suspect negative reviews are fake, competitor-driven, or off-topic, report them through Seller Central's review report tool with the specific review ID and reason.