I like it Rogue! It perturbed me that I needed a tech to avoid being hassled by my watchdogs. And I was further perturbed that once I learned the tech, they still hassled me!
So... units can fortify/Guard from the get go. But they don't get a defensive bonus until the prereq tech is learned. Might as well throw in a heal feature as well. When healing a unit gains no defensive benefit, and maybe even gets a penalty? Requires the same tech as Fortify?
I can't help but think of a tactical warminded mod which brings in field hospitals and healers which add percantage based heal rates. As well as fortifications along the same line.