You won't get them in an hstore[0] column, which was the context of my reply. Of course in a JSON column you want full JSON support, but my and my parent's post were about converting back and forth between hstore and json.
Since hstore only handles string:string mapping, the choice is either to silently corrupt data by stringifying all values in the json->hstore encoding, or erroring out if the input data is anything other than string:string.
The latter would be what I'd prefer, and more in line with usual Postgres behavior.
