I'm having a hard time understanding what they mean to clarify with:
"For example, having overviews from other EVE clients as overlays on one EVE client would allow a player to get real time intel from all those other game instances without having to switch to the other windows."

I don't currently overlay any of my clients, but in the past I have used isboxer to tile my clients neatly on a second monitor and use the focus hotkey rather than alt tab to switch between them on my primary monitor. Is this still legal? If not, how is it different than using the official launcher in windowed mode and positioning all on the same monitor. I can still see all of my huds, overviews, modules, etc. The only difference between the two methods I see is an aesthetic preference.

I apologize if this is clear and I'm just not seeing it; I'm running on rather little sleep at the moment.