I can agree with frozen names. But not banned ones. If you came back to find all their awesome sauce names more or less stolen, what would you think? We can never guarantee a person is going to return, or when they're going to leave. If they're forzen permanently, they're profile pets are going to die. You could probably delete their showroom pets as well, since they're really just going to waste.
But a banned account which will be un-frozen at some day and age, they're profile pets may die of starvation anyway. And then you could retrieve the names from the graveyard. But deleting their showroom pets to top it off? That would be, in my opinion, extremely uncalled for D:<