Peer pressure might be the only way to limit spying. I don't think HT has the ability to stop it even if he wanted to, which is really unfortunate: having (or simply believing that!) your mission was jumped due to a spy report takes a huge chunk of fun out of the game. The two or three known (well, okay, "believed-by-me," but I'm very anti-paranoia) regular spies do seem to limit their presence and behavior when they're called out on it. Maybe more condemnation on country would help.
This is one of the most hurtful (to the game) advices I have heard in a long time.
Why? Because 9 out of 10 "spy" accusations are as all those countless "cheat" and "hack" accusations clogging up all communication channels these days. I got myself accused of using shades or similar illicit means hundreds of times. Literally. Never there was any substance to it. Ever.
Once ago I was amused by this, thinking "it's just jerks, laugh & squelch em". But it's not limited to PM's. You get 'called out' on 200 and of course on their country channel. Again and again and again.
Each time a NOE mission fails or a CV gets sunk a tad farther out at sea there will be the usual kneejerk reaction of "SPIEZ!".
Find the M3 in your whiteflagged town? "You could never ever know I was there, there was no GV spawn! CHEATER". As if you would not shoot at an m3 just because you were actually looking for a landing goon. OR as if never ever someone did that "GV stunt without spawn" before
These days, new players learn that spies and hackers are everywhere in Aces High. Your goon get's shot down? Spy!. Your tank round glances off? Hacker! Bish won the war? HTC bias. (You just wonder why the same people spreading that stuff day by day also keep playing day by day.
It's not isolated nonsense anymore, and for sure it's no longer funny at all.