I don't understand what you're saying here. What I am saying is that human behavior is not governed by the diplomacy engine. Players make their own decisions. So the fact that another player is the same ideology as you (and thus doesn't get unhappiness from your tourism influence, but has your tourism advance rapidly against them) can't stop them from invading you if they think you're going to win. Humans play to win. AIs don't. So there are a number of factors that make tourism much more effective as a victory tactic against the AI than they do against human players. I don't see how that is disputable. Hence, a tourism mechanic that was balanced in multiplayer would almost certainly be too powerful in single player. I just don't see why we would want a mechanic like this. Effectively you are making tourism provide gold, in addition to its current benefits. But as far as I can tell tourism is not underpowered in single player; it doesn't need additional buffs. Now if the effect is trivial in game terms, just a few gold, then it probably doesn't effect balance much. But in that case, why bother? The game should be balanced around the victory conditions that exist, not against some hypothetical game that has different victory conditions. Otherwise it's like saying "if we turn off the spaceship victory, then what do I get for my spaceship parts?" There's no reason to give spaceship parts extra bonuses, because the spaceship victory condition is in the game. We already have an interaction between espionage and tourism; diplomats increase your tourism influence. I am one of the many people who think that espionage in BTS was not very fun. I much prefer the Civ5 system, which is much simpler and more elegant. But I do not think this should be a design goal. Tourism is designed to be something that makes the late game interesting, it is not designed to be something that allows city flipping in the Renaissance era.