I sort of feel like both make sense, and the tension is driven by the strangeness of the way entity_types are shared in GR. In most cases, i'll only be deleting entity_types that I created and no one else is using, in which case this will be a true delete. At the same time, I shouldn't need to know or care if someone else has pushed data to an entity_type i created.

One way to handle that would be to have the entity type DELETE call return an error if anyone else has pushed to it, at which point the client would need to know to call the entities DELETE endpoint. I could be ok with that solution.