> don't include it in the model

They tried that, but they failed because they didn't know that it's possible to downcast from an interface.

It's really hard to have that kind of problem in a dumb REST API. `return {"name": record.name}` does what it says with hardly any magic. But if I write `return record` there's a whole extra layer that grabs information out of record, and I have to trust that it only grabs the information I want it to grab.

This is not to say that dumb REST APIs are definitely better. Having to do things manually also introduces risks.