How to prevent the ban of sites (grids)?

Question

PHP

There is a parent site that ranks well. They want to hang up a personal account on its subdomain(?), which will generate a site with lorem ipsum, but with a bunch of pictures from the main site, at the click of a button. Further, the client can direct this site to its own domain or leave it on the test one. Shouldn't be banned?
I don’t really imagine only the process of generating a test domain, if there is a personal account on a subdomain anyway.

Answer 1

weird private office

Answer 2

Prohibit a subdomain with a specific URL for indexing via robots.txt