Example: I caught Arabia twice stealing lower techs from me (spy wasn't killed). I hadn't stolen one yet from the tech leader. Hence--that Arabian spy is a higher level.
This is not uncommon, and argues as to why putting your first spy in your cap is probably not the strongest play. Yes, difficulty level does make a difference as to what is going to work best. But as you observe, like the AI, the player can be in the tech lead and still steal from an AI.
This conversation is feeling familiar, as you and I corresponded on
the topic several weeks ago. Here is that table:
|none|Level 1|Level 2|Level 3
Chance to Notice|66%|100%|100%|100%
Chance to ID|33%|67%|77%|87%
Chance to kill|0|33%|43%|57%
One thing worth pointing out is that putting your Level 1 spy in your cap means that you are 50% more likely to notice the theft -- but it is still more likely than not that the thief gets away!
So, if you are really
bothered by the AIs stealing tech from you, maybe you are better off
not putting a spy in your cap? Odds of it happening are about the same, but at least you are significantly less likely to know of the offense! Or maybe wait to pull the spy home until
after they have leveled up. That way you are
killing enemy spies at about the same rate you were previously
noticing.
And the higher level that spy gets, the harder it will be to kill him.
No, that at least is not correct. The higher the enemy level spy gets, the
faster they steal from you. Your odds of killing the enemy spy stays the same. (Actually, since they are stealing more often, you have more opportunities to kill them!)