Oh! Yes – now I see what you meant… ^-^; I just read your post but not the original question…
Well maybe what I explained can still be of use to you or anyone else tasked with that matter when creating their games…
Back to your question: Of cause you can also lay an invisible actor in front of a door and turn it on/off by a token to create the effect of a ‘locked’ door! So… Yes that works! 🙂
(I just checked it: If you want to use an event you step up to (not one you can step on), it doesn’t work! The door is triggered even if the event is at the same place as the door…)