Customer reviews: Good/Bad reviews funnel

I am currently checking and digging the patterns of companies that tries to hide reviews if they are negative.
In most of the cases, after using a service, buying something, a provider will sent you and email asking for a feedback. There you will be able to submit a rate (in the email, or via internal page).

If you submit a 1-3 star rating - you will be thanked for leaving a review, or dropped into internal review page where that review will not be visible.
If you submit a 4-5 star rating - you will be sent to TrustPilot.

I understand why this filtration exists, but I would also like to know more patterns or similar tactics that are applied.

Thanks