Earlier quoted context omitted.
The ads are the actual problem. It's entirely possible this is a stopgap solution while they flag the client for manual auditing (or whatever)—manual auditing doesn't scale, so I suspect this is going to be more successful at preventing abuse in the short term.
The problem is that Google has built most of it's products and business around the concept that they can automate away manual intervention. I think they are quickly starting to discover how faulty that concept is. Some of the "AI" startups that mix automated intelligence with human fallback have probably got it much more right: Sometimes, you need people.
Regardless, I think the warning is better than no warning. Again, we don't know the process behind the scenes.