[throwawaysleep]

At least for us, all the translation stuff is frontend, so returning errors from the server is not straightforward. We backend people don't want to deal with anything user related. Sure, the backend needs to validate that it exists/is safe, but it probably doesn't do any of the other validations.

[emsy]

The problem is not the validation but how it’s handled. A client should allow any input to the server and just inform the client that it‘s erroneous. If the input isn’t valid the server will know it. If not that’s a bug.