With version 19 of NIS, with Boot Time Protection set to Aggressive, I'd see NIS in the Windows 7 notification area basically right after the Windows UI started (and the firewall active at that time as well). After upgrading to version 20 (with Boot Time Protection set to Aggressive), the NIS icon only appears after all of my other startup programs have loaded, and I'm able to run applications without NIS firewall dialogs appearing; if I wait for the NIS application to load (evidenced by the icon appearing), then when I run those applications, the NIS firewall dialog does appear.
It appears that Aggressive NIS Boot Time Protection for version 20 is not as aggressive as version 19, and I would definitely consider this a bug.