The model fields defined in django.contrib.auth.models (and I assume other parts of django) use django.utils.translation.ugettext_lazy to specify the label (or another property from which the label is derived). The form field objects generated by form_for_* and ModelForm? on these models return a django.utils.functional.__proxy__ object instead of a unicode object where ugettex_lazy is not used.
I have a few helper template tags which are trying to alter the form field label with a concatenation, which is throwing an error for form_for_model and ModelForm? forms for django.contrib.auth.models.User (and other django/contrib models that use ugettext_lazy).
As the documentation doesn't recommend or require the use of ugettext_lazy in it's examples and tutorials when defining models and forms, this inconsistent behaviour seems less than ideal. If django.utils.functional.__proxy__ could be changed with an __add__ (and other?) methods to behave more like a string/unicode object, that would be good?