Plugin appears to work very well. Had to make a minor style change to get it to integrate well with my page as the checkbox width was inconsistent; this was easy to do as all that was required was to comment out line 322 which contains:
gasp_cb.style.width = "25px";
Other than that, the plugin does what it claims and does it well. Would love to have a stats page just to see how many attempts were bounced but I guess that would require persistence and I do like how it doesn't require additional tables in my WP DB.