No, I think it would actually be a relatively simple thing to build, depending on the requirements and the sofistication of the module of course. Considering the complexity of some of the modules

I suppose you googled the silverstripe/robots combi? I found this one http://addons.silverstripe.org/add-ons/tractorcow/silverstripe-robots

It lets you config robots.txt from the yml config ánd exclude all pages that are not included in search. Also it disables the entire site if you are in dev mode. Maybe this would do for now, or be easily extended or used as example by your coders?