Doesn't this seem a bit "low stakes" to want more disclosures about? I view it in the same light as say someone who posts makeup reviews or video game reviews on YouTube- often it isn't their primary source of income, and the item value (<$100) seems notional. Maybe it can be treated as more of a deal if a company were to attach stipulations or keywords for the reviewer to mention, at which point it should be treated as a partnership rather than a less-than-impartial review. I subscribe to independent creators on Patreon because bias is nearly impossible to avoid when there's a quid pro quo of getting a stream of free things from companies.
often it isn't their primary source of income, and the item value (<$100)
Neither of these things magically make your review more trustworthy.
Getting free stuff taints your review, and it doesn't matter if it is low value or not. And to be fair: People get their utilities turned off for these amounts. These amounts keep folks from affording medicine. Some of them simply wouldn't be able to review so many games if they didn't get them for free.
People are more likely to view the company favorably if they are getting the product for free - and are likely to review games they wouldn't otherwise review. They should reveal this sort of bias. And it doesn't matter if you are "low stakes" or not.
Many board games are funded through crowdfunding, which regularly reach 7 figures, so there is big money here. There has been controversy recently about YouTube “reviews” of active kickstarters which are actually undisclosed paid promotion, and in one case attempting to extort sponsored videos to prevent release of negative videos instead. So there’s a bit more in this than a free board game.
