When looking at a friendly tiddler javascript needs to know if this tiddler is a) from this space and (maybe) b) writeable by the current user.
Otherwise it is difficult to make a decision about things like "adding a widget with a link to whatever the current editor is", as done in editedit.js.
At the moment this information is available on the api (tiddler.html) but not friendlytiddler.html.