Perhaps it is a matter of mission size. It is difficult to "hide" a mission of 15, 20, or 40 people. Maybe limit the size of the mission to make it eligible to not be seen by anyone.
I think the "my mission was busted by spiez!!" paranoia is getting a bit out of hand anyway. Most busted missions are found out because someone just happened to be there as your hord passed by. I've spawned into another base in a gv just as ten Bf110s pass overhead going in the direction I've just come from. I've been in missions that have flown over an enemy cv, missions that have run into opposing missions going the other way.
If you are so paranoid that you are being spied upon, don't advertise your missions at all. Tell the people you usually have in your missions, set up a base and time to take off. Make it an intimate affair. Don't announce it over country channel, at all.
The whole point of radar, both ways, is to find the fights and get to them as soon as possible. Not for any offensive or defensive, country strategy but as a function of game play. It sucks to have to fly around forever not finding anything to do. Everyone freaks out when HQ goes down not because they can't find the enemy, unless they are within a base dar, you don't know where they are specifically, but because they can't find "where the action is".
Like I posted somewhere else before, if you want no opposition at all, why are you playing a MMOG? If you are constantly failing to take bases with some opposition then you aren't doing something right, spiez!! or not.
wrongway