Note that you're excluding a middle that is perhaps worth considering. That is, the choice is not necessarily between "dealing with" a user account on an admin level (which generally amounts to forcing the user to change their ID and not much more), and spending hundreds of thousands of man-hours in counterproductive exchange.

A third option worth considering is not engaging in counterproductive exchanges, and focusing our attention elsewhere. (AKA, as you say, "don't feed the trolls".)