And since the large maps are out of rotation, it makes looking for a CV a relatively easy task, especially with some of the newer maps. But even with the larger old maps, if a CV was hidden, I can guarantee I know within a 4 grid area where it was hidden depending on what side of the map. No spies needed.
Same with tracking dar bars to strats to shoot down buffs, or assuming which undefended base off the main front Bish are going to try and sneak next...
Just yesterday. My sides' CV was sneaking to a non active part of a map. Then bombers took off to sink it. Immediately the accusations started. When I pointed out that it was just sitting off a base, so that it easily could have been spotted, the reply was "But they had no reason to look!"
(Sorry, you folks might forget about CV's until the base starts to flash but this player regularly checks coastal bases by .dt command and in person.)
Or on Grinder a small map with very few places to 'hide' a CV.
My side did just this. Enemies are scouting for it, along the coast. One set of bombers flies several sectors along the coast, unopposed. Then, when he finally entered the CVs' dar, "SHADES! How else did he knew it was there" - By effn checking every other sector until he finally found it!
Even better, the CV wasn't sunk, so the enemy came back half an hour later. Of course, this time on a more direct course. "CHEATS! SHADES! SPIES! He flew directly to it, that proves it!"
I could give hundreds of such examples, literally. Not even counting those where I was the accused myself...