moistfinger: Your idea is correct. I HAVE doubled from the bar before, not often, but not never either. It is a good play in some situations.
I wouldn't want this option to be taken away...

Note that if you CANNOT double (because the opponent has the cube, or it's post-crawford), it DOES Autopass.
So it is not an be-lazy-and-save-some-code-problem, in the contrary, it is doing it even more detailed and correct.