i.e. I want the output to always come out using black only no matter what the settings are in Indesign.
Assuming that you are printing to a PostScript printer, the answer is absolutely not. In the case of PostScript, InDesign and its underlying Adobe Core Technology components generate their own PostScript (OS PostScript drivers typically cannot handle the full imaging model of Adobe applications) and thus, driver settings are irrelevant for most such output, although InDesign does attempt to “pick up” certain current PostScript driver settings associated with paper size, duplex, etc.
Steve, they are using Windows xp, in design cs6.
It is a restaurant that is printing black on their menus, but they create their menus in InDesign. Eventhough we are using a monochrome print driver, if in InDesign the person printing (not graphics people) don't change the "composite cmyk" default to "composite greyscale" it still prints using a 4 color process to produce the black and they get hit with a color charge on their MFP.
In InDesign CS6, they can export a PDF file which is grayscale. Choose File > Export > Adobe PDF (Print). Choose a PDF preset like Press (but not PDF/X-1a which doesn't support this output). Click on Output and choose Color Conversion: Convert to Destination. From the Destination menu, select one of the grayscale profiles like Dot Gain 15%. It will produce grayscale output, only on the black plate.