gdi works differently on the different servers - there are clues on the join gdi page on each server and on the details page for each server on the portal page, but to my knowledge there is no comprehensive source that outlines the differences on each server, the rationale or motivation for these differences, their implications for game play or the similar but different limitations placed by "humanitarions" -- and not all of what is posted is accurate or uptodate -- you just have to learn by asking and trying

for tourney only:

SO:
Why can I not attack back?

the 2x limits are by nw at the moment you attempt the attack or the op

Why can I not spy?

same as above

Why did the other player not have to declare war before he attacked?

he was within the 2x limit when he did what he did

Why is the GDI still blocking me when the other player has already sent multiple attacks and offensive spy-ops at me?

the past is meaningless when the 2x limit is considered --- on tourney, the past is almost always meaningless as there are never any restrictions on the attacks or spyops you use except for the end of set rule about not being able to attack a player in the last hours that has not attacked you at least twice

manipulating your nw to use gdi to your advantage is just part of the tactics of tourney as it is played today

and if my nfo here isn't correct, i hope someone else will correct it

good luck!