I'd imagine it depends on your parser, and if non-browser JSON gets more prevalent it'll probably be addressed. JSON has no format specified that I'm aware of, but some browser-like parsers will handle things like this:
{"key":"value" // comment
or
{
// comment
"key":"value"
Which I find wholly acceptable (though poorly supported).
Wouldn't that only work if the json/javascript is pretty-printed and not minified?
I'd think this problem of comments in JSON requires a solution that is part of the JSON specifications rather than dependent on individual parsers implementations.
Or perhaps JSON only really shines as a data interchange format and not much else.
