Using toolbars modes considered safe ?

I am using the Navigation toolbars mode and I wonder if I should the attribute or if it can change in a future release ?

The attribute I am talking about is defined in in NavigationToolbar2 in the __init__() method:

            self.mode = '' # a mode string for the status bar

The strings saved on the panning and zoom mode are kinda unconventional:

            self.mode = 'pan/zoom mode'
            self.mode = 'Zoom to rect mode'

Having the zoom word in both strings can be confusing, moreover they should start either with a lower case or upper case.

                Can't they just be "zoom" or "pan" ?

Having just one word as a mode will remove confusion and make them easier to test when you are adding modes to the toolbar ...

                                         Just a suggestion.