Ahh, I see -- for 0.6, then, `None` will be equivalent to `[]` (old behavior, with the addition of a deprecation warning). This makes sense, since users will at least be warned that they are not getting bad channels using `pick_types(info, meg=True, eeg=True)`. Then, in epochs and evoked I will make the default picking with `exclude='bads'` to deal with the dropping-due-to-bad-channels issue. Sound about right?

While I would also like to make the default to `bads` in 0.7, if you and/or others don't want to make that transition, we could in principle just leave the default `None` with deprecation warning to force the user to make a choice. However, I expect most folks in most situations will use `bads` and thus it makes a natural choice for the default.