Creating User Event script errors

The code sample in the docs seems incomplete.

It says you can create a UserEventError like so:

require(['N/error'],     function(error) {     function createError() {        var errorObj = error.create({           name: 'MY_CODE',           message: 'my error details',           notifyOff: true }); }     createError(); });

But this only creates the error object.

Is the next step to "throw errorObj;" ??

When I do this, the UI returns a SuiteScriptError, not a UserEventError. Am I missing something?