Answer
Not if you only need the field for the Report Rule's own condition/action logic, rather than actually printing it on the report layout — in that case, you can use a SQL select statement directly inside the Report Rule itself to independently retrieve the value you need, without touching the report's underlying view at all. A Developer Studio customization to add the field to the actual report view/layout is only necessary if you need it to appear as a printed field on the report output itself, not just to drive a Report Rule's logic.