In case you're not aware (and for anyone curious enough to look), the extension was changed dramatically within days of when the story hit the fan. It's really hard for someone as inexperienced as me to tell what was actually run! https://github.com/mozilla/addon-wr/commit/7d4e422bf573f675b...

I believe it did technically run enough code to decide whether or not it was enabled, and I'm not sure whether or not its installation was avoidable (I believe enabling SHIELD studies is opt-in [perhaps part of opting in to analytics?]).