Unity and spies

So Unity 5.1.0f3 just came out. I updated. Wish I hadn't. Because now it crashes while it tries to show the splash screen. Reinstall, registry cleaning, removing every Unity-related folders I know of, installing in a different place (what if bad sectors are the problem) - nothing has helped. Maybe I'll just give up and revert to 5.0.1.

So while there are no updates code-wise, I thought I'd share my struggle with the spy unit. Initially, I thought the spy could be a scout-like unit and that's all. But it wasn't as exciting as I think a spy unit should be. Sun Tzu in Art of War distinguished five types of spies:

"Hence the use of spies, of whom there are five classes: (1) Local spies; (2) inward spies; (3) converted spies; (4) doomed spies; (5) surviving spies"

So what are these?

"Having local spies means employing the services of the inhabitants of a district."

The spy "system" in its current form doesn't let us do this. So how should we incorporate it in the game design? Bribe enemy towns, maybe? What should that result in? Could we see a few tiles around the town? Should the cost be defined per turns? What would deter somebody from just buying all towns? Is it a life-like scenario? (While we're at it, is this game life-like at all?)

"Having inward spies, making use of officials of the enemy."

 Bribe enemy spies? What would deter a player from just hiring all enemy spies?

"Having converted spies, getting hold of the enemy's spies and using them for our own purposes."

When we would kill a spy, should the game ask if we want to kill or convert into a double agent?

"Having doomed spies, doing certain things openly for purposes of deception, and allowing our spies to know of them and report them to the enemy."

This would be fairly straightforward: assuming one of our spies is a double agent, we could move our units in a way that makes the enemy do incorrect assumptions. This only requires the game mechanics that lets a spy to be a double agent. Which is the harder part.

"Surviving spies, finally, are those who bring back news from the enemy's camp."

It's just sending a scout into the enemy lines. The kind of spy the current system has.

The concept of bribing seems to come up regulary at the spy types. If I were to implement it, how should it work?

• Should the player capture a spy before it can be bribed? Not a good idea: the other player - seeing the spy had been captured - could just kill the spy and hire a new one.
• Let the player bribe any spy anytime? (At least those who are visible to them.) Not a lot of players would use spies then - they could be seen accidentally, and then they are better off dead.
• Hire the spies with some user-given cost, and let the other player bribe any visible spy at any time, with a custom cost, and if the cost is higher then it is converted? In this case, the players should not know if the spy is still theirs, because then they just raise the cost, and then they are OK. But how we make sure none of the players know if it is actually still their spy or not?
• Place random units instead of what's actually there. I don't like this idea, as I'm not a huge fan of randomness. This game is all about a minimalistic warfare simulator, without any random chance whatsoever. It would also be somewhat hard to implement.
• Doesn't update the fields that only the spy can see. It might actually be a usable idea. For some reason it still doesn't feel like it is, but I can't tell what is my problem with it. Just as with the spy-betting system: I sense there is something wrong with it, but can't tell what

 These are the ideas that I had so far. I'm not sold on either of them so far. It might be a decision that needs playtesting to figure out which is right, or maybe I got some other idea. For now, I'm going to go with the "spy-as-a-scout" plan, and then work out the details when it's time.