Sorry for the late response. Yes, gifting gold can be part of this strategy although doing it explictly then turning around and taking it back is IMHO borderline exploitative in the harshest sense. What is esseintally being done is not only make an impossible trade possible (in 1 turn) the human player is taking advantage of a double counting of the attitude modifiers. The AI counts the gold gifting as a positive modifier and then the following trade as another positive modifier. Although the concept of a machiavellian game relies, in part on understanding in abstract fashion the geopolitical landscape and perhaps, exploiting the AI's blind spots, it is really more about power management than overt cheating by getting the AI to double count attitude modifiers. In this sense, the strategy is valid and a variant of it may be included in a future update (this strategy piece is still not finished). What I would suggest is to do it more indirectly. Gift them gold to allow them to develop their economy, rush build buildings (if they are in the correct government). You can then return to them and profit from an improved economy. Your cash infusions would allow them to pay for the goods they want from their own tax base. Part of the idea behind a Machiavellian global management game is to use foreign capitals to your advantage to negate the crippling corruption of actually holding on to a client state's cities and the cost to defend those cities.