This is definitely possible.
The way I would approach this is to:
1. Find all keynotes in the project
FilteredElementCollector tagColl =
new FilteredElementCollector(doc).OfClass(typeof(IndependentTag))
.OfCategory(BuiltInCategory.OST_KeynoteTags);
2. Search through those keynotes to find the ones matching the text you want
List<IndependentTag> keynotesMatchingText = (from IndependentTag i in tagColl
where (i.get_Parameter(BuiltInParameter.KEYNOTE_TEXT).AsString()
== "MyText")
select i).ToList();
3. Get the views that own these keynotes
List<ElementId> viewIdsContainingKeynotes = (from keynote in keynotesMatchingText select keynote.OwnerViewId).ToList();
Note that this will only get you the views containing the keynotes, and not the sheets that contain the view.
With the keynotes matching your text and the views that contain them known, you should be able to come up with some way to verify that you haven't missed any.
