Information leakage has been going on since the very start. And most - if not all - travelers eventually leave or haven't been around long enough to have been the spies from the very beginning. Either the giants are always lucky to find Travelers willing to destroy their own world, or they found an Asgard native and nobody noticed them so far.
In any case, I trust the travelers a lot more than the natives. [ or satan could be the spy, yeah. ]
[text]
In any case, I trust the travelers a lot more than the natives. [ or satan could be the spy, yeah. ]