Not surprisingly, kindle unlimited provides new and improved methods by which authors can engage in review swapping - with KU, for just $9.99 per month, self-published authors can review swap one another AND get a download payment.
If the $1.88 payment that I have seen bandied about holds true, it will take only 5 tit-for-tat swaps with a "read" to 10% to pay for participation. Anything above that is just free money at amazon's expense.
At least one Goodreads group has already started to take advantage of this wonderful opportunity.
It currently has 117 members. Maybe, though, if enough authors Scam-azon, Amazon will decide to give a shit that their review program is in shambles. I'm not holding my breath. You?