I have to agree with the other bloke, this is very much a problem in certain 'magical' JSON 'serializers' in certain very popular server languages, e.g. Java, S

I have to agree with the other bloke, this is very much a problem in certain 'magical' JSON 'serializers' in certain very popular server languages, e.g. Java, Spring, FasterXML. I've seen JSON ser done right where you do just ser/deser direct from/to a JSON object, then perform a manual mapping to domaim or business objects, I've seen it done the wrong way where the domain and data objects are highly coupled, by default. I think the OP is bemoaning that being a common practice.