Just to verify what's going into the error bars RooUnfold returns, I unfolded our pi0-triggered (9 - 11 GeV) data twice (with all of the same unfolding parameters): once with all of the default options in RooUnfold, and once the line 'unfold -> IncludeSystematics()' explicitly called.  If we weren't including the systematics (due to finite statistics in the response matrix), then the case with explicit call should have larger error bars.  As you can see below, this is not the case.  The default error bars include these systematics.