Exposed filters: reset last value query string

I created my own module that replicates a given view's exposed form into a separate block for showing it on any page sidebar.
The module has been based upon these snippets:
http://drupal.stackexchange.com/questions/8746

The problem is described in detail here: http://drupal.stackexchange.com/questions/8083 - last value got sticky and prevented new searches on view's principal page.

I think we should have a UI setting/api function to reset the exposed filter's values (query string, last value session variable) to reliably perform new queries. Remembering last values is a very nice thing to have, it just should not interfere with user action.