This is a neat idea but...

... it means that config files won't follow the official JSON specification. No JSON tool will function unless it's run through the _json_parse() function. My concern is that this will be a barrier for usage.

Another convention is for comment fields to begin with underscores ("_"). So you might have '_personal_data' as a comment like so:

``` javascript
{
  "_personal_data": "This is where personal information gets stored",
  "name": "Danny"
}
```