If I remember correctly the approval was likely automatic. So, I suspect you could pay to have certain keyword filled reviews automatically be disapproved--obviously this would only be used to filter out swear words or proprietary details of the company.
"Your trust is our top concern, so companies can't alter or remove reviews."
But, I noticed from a past review that there is some kind of 'approval' required. So, yes it seems they can remove reviews by not approving. Sigh.