I attended Tony Alvarez's workshop at Aiki Expo, the theme of which was partially focused on maai. One of the points that was raised during the workshop is that maai exists. That is to say, given two individuals who are engaged with one another, maai is not created, performed, etc. by either individual. It exists as a characteristic of the distance and timing of motion between the two.
For this reason, it can be influenced by either party (by how they move), and how one influences maai could be a technique. But to say that maai *is* a technique is sort of like saying that the road is a vehicle.