For the few of us that have been studying the various fake and incentivized review issues on Amazon over the years, and for those of us that have access to real diverse data samples — this is sort of a nightmare and it is going to swing Amazon fake review problems right back to where they were in 2014.
I wrote up an article about it here, but basically these "legal" incentivized reviews that Amazon sanctioned as okay for sellers to use completely stopped the flood of hard to detect fake reviews that were a nightmare on Amazon prior to 2015. Now there is huge incentive for sellers to return to that model, and meanwhile the companies that introduce reviewers to sellers for product review exchanges have already found an easy loophole in the new TOS.
Huge PR move by Amazon. Two years from now, the fake review issue is going to be considerably worse.