"Philip Morris cannot prevail on this issue at summary judgment because the government need not show that nobody under 21 would have smoked but for the RICO violations. As we held in First City Financial, 890 F.2d at 1229, “disgorgement need only be a reasonable approximation of profits causally connected to the violation.” In First City Financial, we found that the district court appropriately ordered disgorgement of all profits on a stock sale where the defendants failed to make a material disclosure, purchased stock whose value would likely have already risen had the disclosure been made, and then sold the stock for a killing after the undisclosed news broke. See id. at 1229-32. Although the government never proved that all increases in the stock’s value stemmed from the violation, we rejected the defendants’ argument that because the increase in price may have depended on other factors, disgorgement of all profits was “simplistic, quite unrealistic, and so de facto punitive.” See id. at 1231. Noting that “[r]ules for calculating disgorgement must recognize that separating legal from illegal profits exactly may at times be a near-impossible task,” we held that “the government’s showing of appellants’ actual profits on the tainted transactions at least presumptively satisfied” its “burden of persuasion that its disgorgement figure reasonably approximates the amount of unjust enrichment.” Id. at 1231-32. Although recognizing that this might result in “actual profits becoming the typical disgorgement measure,” we observed that “the risk of uncertainty should fall on the wrongdoer whose illegal conduct created that uncertainty.” Id. at 1232; see also SEC v. Banner Fund Int’l, 211 F.3d 602, 617 (D.C. Cir. 2000)."