Will actually only occur if the url is 'fiddled' with...
error received:

Internal Server Error: /tag/filter/results
Traceback (most recent call last):
File "/home/www/platform/env/lib/python2.7/site-packages/django/core/handlers/base.py", line 111, in get_response
response = wrapped_callback(request, _callback_args, *_callback_kwargs)
File "/home/www/platform/django-mpowering/orb/views.py", line 159, in tag_filter_results_view
{ 'filter_tags': filter_tags,
UnboundLocalError: local variable 'filter_tags' referenced before assignment