It's easier than that. If she's posting all 5-star reviews on products that don't get rated 5-stars by other customers, those other customers shouldn't be seei

It's easier than that. If she's posting all 5-star reviews on products that don't get rated 5-stars by other customers, those other customers shouldn't be seeing her reviews. Preferentially weight the visibility of reviews from reviewers who match the individual customers reviews on other products. This incentivizes users posting honest reviews and makes 'gaming' the system almost impossible.