Several times now, I've accidentally Cmd+Q'd Chrome because I didn't realize that TextEdit or Preview was no longer the application in focus.
This happens mostly if I just closed the last of the application windows, and accidentally expose'd the windows back and forth. If you "Show Desktop" and then bring the windows back, TextEdit and Preview will now be closed.
I don't think I like it, but it might just be a matter of retraining myself.
Don't add some non-deterministic 'feature' that messes up my model of where my apps are. If you must quit an app to recover resources, do it whilst pretending that the app is still running, because that's my model.
Perhaps, in regularly cmd-tabbing to running but documentless applications, I am some kind of uber edge (head) case, but I suspect not.
As a user, I don't know when the app will go away.
Perhaps if you really think about it, it's deterministic, but it's 'casually non-deterministic'.
So yes, I'll admit to abusing the term in its pure sense.
Screenshot of how to enable it: http://jhn.me/9BDE