I guess you can't take away any of the planes that seem proportionately too expensive for them to have recently purchased eh?
The problem with that is while I have already taken the estimated total amount of illegal profit, I would have to go and estimate the ROI. ROI is not that easy to estimate because it depends on a various factors. It is also compounding as time goes. The time-value-money aspect is an issue that I am not really willing to get into although it would make the punishment more effective. The main problem is it takes forever to access the penalties and is not feasible to do in mass.
Another issue is that what if the planes are on routes? Should we access those routes, their profits and returns as well? That would be a lot more to deal with.
If we don't access the time-value-money part of the benefit, taking planes or cash doesn't make that much of a difference. Right now, we tend to use a fixed amount of airline value as the additional penalty, which hopefully accounts for the returns.
With reference to the notion of "perceptual deterrence" under the deterrence theory of criminology, the subjective perception of the punishment is more important than the actual objective reality. We would love to put all players back into the fair playing field, but we are also realistic. Our primary goal is to deter players from violating the rules in the future. Through quick, certain, and severe punishments, we hope to deter both current and potential offenders. The notions of swiftness and certainty are two factors that we have to take into consideration when selecting our punishment method. If we choose some complicated penalty accessment methods, it would take up too much time, and instead of hunting offenders down, we would be playing with our calculators trying to figure out the penalty. That may not be a good scenario.