I would assume most of them just happened to stumble upon it. I also assumed must don't leave once they find it, so word of mouth is just moot. broadcasting its location just seems like a death wish as well...

Kinda like a luck of the draw, but I could be completely fucking wrong and stupid for saying something like this idk m8

[quote=@Assallya]
Telepathy?  Jedi don't have telepathy. 

Worse still... if there was some sort of Telepathy thing going on Vader and The Emperor would be in fits laughing on the floor trying to find the strength to issue orders to the fleet to wipe out the sanctuary.

I also think it would take a bit longer to get the word out.  After all, the story involves the "last of the survivors".  If the sanctuary were put into play instantly entire orders would be showing up instead of the few survivors of each.
[/quote]

http://starwars.wikia.com/wiki/Telepathy

idk according to the wiki they can. 

Edit:Wouldn't say it's a direct type of telepathy, nor would all jedi be able to do it.