99% of the time it's obvious. Change places with Shaka - in his position who would you think traded Gandhi the big tech he just got out of nowhere?
Wrong. It's obvious in this dumbed down example. In the case of an isolated human with techs being traded between an AI and human as well as same AI and other known civs, the owner of the techs traded isn't obvious at all...especially if said tech has multiple people knowing it already or if there are MULTIPLE yet-unmet players that could have made the trade.
99% is a rather flagrantly asinine assertion to try to handwave the fact that the AI is, in fact, cheating in this regard...because it will *always* know the trade happened complete regardless of whether it was possible for a human to detect it. Do a real test or drop that nonsense 99% assertion.
It's arguable to some extent that trade with known civs granting a demerit is cheating too. There are some situations that, due to IBT trading of the tech further, a human couldn't figure out who traded a tech to which civ consistently...
You can't squirm out of the fact that the AI cheats here, sorry. Not unless you can tell me which unmet civs traded with the AI next to you and when...and exactly what techs (because AI demerit is based on valuation of the tech trade). You can't, and therefore you are wrong

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Thats imo bad code, not cheating.
It's cheating. Cheating might also be due to idiot programmer code, but it's still cheating. We've been through this before. I don't know how to help you if you insist on continually ignoring the English dictionary in favor of using your own definitions for words.
http://dictionary.reference.com/browse/cheat
verb (used without object)
4.
to practice fraud or deceit: She cheats without regrets.
5.
to violate rules or regulations: He cheats at cards.
I'm sure you can find dictionaries that require intent to violate rules too (however, we have no way to prove or disprove intent in this case). However, the fact remains that what the AI is doing in this game fits multiple dictionaries' definition of cheating, and therefore your bogus assertion that it's not cheating because the developers didn't intend for it to happen (a very very weak assertion anyway in 3.19 when they've known about it for years before making the patch!) has been effectively defeated

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