Yesterday I just made a [change](https://github.com/jquery/jquery-migrate/commit/d87d7ec29343043ea1049c41bedb571fee32036a) in  Migrate to warn about `null` and `undefined` being passed. Turns out that Android 2.3 doesn't like `JSON.parse(null)`. We still return null but it seems bad form for the caller to pass anything but a valid JSON string here and I'm not sure it's good to define the results of cases like that anyway.

I don't think we want to enter the business of fixing these quirks in JSON strings. If they're security related we should get the vendor to fix them even on old versions. If they're just sloppy, like the `0101` in IE9, well that's not valid JSON and the user will find out eventually. Even the json2.js check was meant to be a security check as I understood it and not a full validation.