Unless I'm missing something,that kind of masking behaviour is what typically causes me to exit an app and manually give it a low review. Are you saying you are actively gating the reviews? :-/
But now the growth hackers of the world had the brilliant idea to treat bad reviews like "the user isn't ready for a review"
Some app-store marketing guru told the startup I'm contracting with, that this is the way to go, because you're pretty much f*cked if you get reviews below 4.
Basically, once some start gaming the system - the others have to follow or they are dead.
It's similar to how irregular migration or general screwing over of workers works: if some farmers are paying 'under wages' or some factories are 'undercutting' ... then the others stand to lose business and are sucked into the same practices.
It's one thing when a massively successful entity like Amazon does shady stuff, but for most businesses ... it seems to often be kind of a quandary.
Its sad that this is the way things are done but what can you do about it really? You can't fight every battle you need to pick what matters