We should talk about [bug 852425](https://bugzilla.mozilla.org/show_bug.cgi?id=852425).  Basically what you have here is true if one uses sufficient try/catch statements, but if you request pb permissions and you `require('sdk/panel')` then `require('sdk/panel')` will [throw this error](https://github.com/mozilla/addon-sdk/blob/master/lib/sdk/panel.js#L31-L33) and depending on when the `require` is used that could cause the add-on to fail to load.