Yep staff used to periodically clear names off accounts but it was a very tedious process that took ALOT of time as, I think, they had to clear each pet individually.
from what I understand they will implanting a way to mass clear pets/ names in the upcoming V4 so hopefully that will happen with in the new version.
Inactive accounts wont be touched.
there isn't a release date on v4 yet so at the moment I'm afraid you wont be able to get to the names ;n;