So by default your instance respect mod removals.
You can change that as a server admin, so comments would remain visible to other users on your instance.
I think your instance is authoritative for content of comments, but the community hosting instance is authoritative for which comments are approved (other instances respect such removals by default)
No, this will only lead people without access to Google Play to be forced to get it from somebody who has modified the app to fake the check.