So in this game, my future Heroic Epic city spot was taken. My settler has no good place to go. So in a whim, I settled it in a deserted spot between Boudica and Julia. Then I liberated the city to Boudica. I got permenate diplomatic bonus with Boudica, and created tension between those too. You think it's worth it?

Depending on the situation it might very well be worth it, but in general it is hard to say.

Sounds good in theory. But I reckon you'd have to be careful because if you get stuck with the city there's no way to abandon it. In terms of creating tension between the two AIs, they probably would anyway without your city. I'd only do it mainly for the diplo points.

have you choped everything and whiped like hell before that:)?

better if you are IMP, one settler from a chop is so small a investment.

good choice.

The only problem with this is that leaders sometimes don't want the city. If there's immense cultural pressure, I've seen AI's refuse to get a city.

The odds of them accepting a city are greater if the city borders their culture.

I remember Obsolete doing this in one of his walkthroughs. The city ended up under enormous cultural pressure (WWE Capital) and was packed with a big stack to prevent flipping. Plus, it provides an easy espionage target.