On the one hand, yes, on the other hand it would also not be too hard to do routing based on such a parameter and Antrophic has shown (through Fable and Mythos) that they have such a transparent routing system in place.
In fact, since they have some rule based system (if bioenegineering or security, route to degraded model) it would be almost trivial to add 'user has filed feedback' to it.
Not saying this is what happens, but just that it's not as insane as it sounds.
I could totally see them running an experiment to test user's stickiness/quality perception with decreased model performance. Facebook was doing exactly this in 2016. They tested the loyalty of Android users by secretly introducing errors that would crash the app to find the threshold at which a person would abandon. That was 10 years ago - imagine what the state of the art in user manipulation is like now.
Its truly naive to think this is impossible or even improbable. You can say there's no proof or that its not the case but certainly much more has been done to juice 5 star ratings.
Random performance is random, your brain will jump through hurdles to fit patterns where there aren't any.