[Phantasm]

Originally Posted by malloyd

Centrum on the other hand does, and yet is still attempting secret infiltration.

Keeping the Paratime Secret is a genre convention. Like it's close relatives the Prime Directive or not telling the public about the monsters, it isn't a particularly sensible policy even considered with respect to its stated goals, and so isn't something you should try too hard to explain.

"A person can be smart. People are stupid, panicky sheep." - Agent Kay, Men In Black

That's the reason for the Secret in a nutshell. The Powers That Be and the the general populace of timelines unprepared for it will generally panic over invasion scenarios. There will be small groups inside such timelines with saner heads and maybe even a "hey, neat!" attitude, but they're the exception, not the rule.

Just because we here on the forums tend to be in the "hey, neat!" camp doesn't make us indicative of the world at large. ;)