I just stumbled across a very specific case where lost context can occur on OS X desktop AIR app. If you use PrintJob and initiate the native print panel, context will be lost on the mac desktop Stage3D window after a PrintJob.start.
This isn't a big deal since in my desktop AIR app I am already setting handleLostContext = true just to handle the Windows runtime case since we all know this is a more common occurrence.
While it is common practice (and even mentioned in the Starling docs) that you shouldn't normally need to set handleLostContext = true on either iOS or OS X, I think it might be prudent to mention this could be needed on iOS or OS X if other native window/dialogs are also triggered by your app.
Others seem to also trigger lost context on iOS when using certain ANEs that trigger other OS windows. It is probably the case that most apps still won't need to turn it on, but good to know if you are planning to trigger other native windows.
It isn't clear whether these losses are unavoidable by Adobe/Stage3D or just cases they can improve upon to avoid lost context. (other native windows like Save/Open dialogs on desktop don't cause lost context on OS X, also the CameraRoll.browseForImage doesn't on iOS)
(I know most of us would prefer a world where lost contexts are non-existent)