Default method/reference parameters to empty string

Some functions define the default of their Source Method and Reference fields to None instead of empty string (''). This sometimes leads to those fields being populated in CRITs with the actual text "None". However, if the data is pulled from an upload form, the field is populated with an empty string. It would be better, and more consistent, for these fields to simply be left blank if no data is provided, so we don't end up with some blank fields and some None fields.

Anybody see a problem with this?