It's noted, for that case, as "expletive" because it's unnecessary. "Or we won't..." versus "or else we won't...". [EDIT] though you're correct that that usage

It's noted, for that case, as "expletive" because it's unnecessary. "Or we won't..." versus "or else we won't...". [EDIT] though you're correct that that usage is not uncommon, to be clear.