Paid review service stars in search ads - why is that allowed?

[PaulS71]

I'm looking at paid review services like Trustpilot, FeeFo and others.

I'm told I can filter out bad reviews, which I can't do with my Google Certified Stores reviews.

I'm struggling to understand why Google include these in the reviews it uses for the star ratings in search ads. I know it's a different thing, but surely these reviews are in breach of the rules that Google apply to their own "My Business" reviews? They talk about "Conflict of interest: Reviews are most valuable when they are honest and unbiased" here:

https://support.google.com/business/answer/2622994?hl=en

Does anyone have a take on whether Google will drop these as the momentum builds in collection of their own reviews?

Thanks, Paul

[MiriamEllis]

Hi Paul!

Would you be able to link our community to an example of Google results for which you're seeing these stars? I think it would help. Thanks!