Add an Is Summary checkbox to the Field Properties Dialog box in Domino Designer.
By default the value would be true.
Deselecting the option would mean that NotesItems created via the field would not have the Summary property set.
The most important benefit of this option would be that data entered into such a field would be eligible for Document Compression by a Domino 8.0.1 or greater server.
Using this option for fields which the developer knows will not be displayed in Views would also help to mitigate the 'Less than 32Kb of Summary Data' problem.