For SR to apply i imagine it depends on the underlying set of SR cards/etc. If you're just topping off on well known material then SR can't do much - but if it's well known material, there's often not even a review stage to have - all the material won't be flagged for review.

However if you have several items that you're reviewing then the SR algo has determined you don't know it (or perhaps they're new, but that's a bit besides the point).