I'd like to know as well.  I change the action to "get" and added it as a field in my Site Form, but it still not passing the values via the URL like I expect a Form with action=GET.  My SEF is disabled.

Seems similar to this bug https://github.com/Octopoos/SEBLOD/issues/305

I figured out part of my problem and was able to post the field I wanted using GET, but it keeps going to my home page instead of self.  I tried all other targets, but they did the same except "blank" which didn't allow for the form to be submitted.  I was trying to use this in a single stage form and a multi stage form and after submission I was redirected to the home page for both types.  I must not be using this plugin correctly.  An example would be great if anyone has it.

I could't get this plugin to work correctly with GET myself, so it is hard to give you any working examples.