While CRS credits Millerwise with indicating that the order will cause the Treasury's Office of Foreign Assets Control (OFAC) to primarily go after foreigners, it criticizes the order's "piggybacking potential":
The issue is whether the executive order's application to anyone who provides "support" for a designated entity might affect U.S. persons inadvertently involved in some form of assistance, such as arranging transportation for, selling consumer goods to, or providing routine legal assistance to an entity that becomes blocked under the executive order. Could U.S. persons find themselves designated under the authority of the executive order and thereby have all of their assets subject to blocking whether or not the assets have any nexus with the transaction of any blocked entity or with any foreign entity?
The report says we can't answer that question until OFAC releases a set of regulations covering how to implement the order. Nothing so far appears to be forthcoming, despite Millerwise's comments to TPMmuckraker creating what CRS calls an "expectation" that OFAC will document its rules for implementation. It's also not clear whether interest from a particular member of Congress prompted the report -- and, if so, which member.
(Via Steve Aftergood, who observes, "the potential application of the order appears to be technically unlimited since it includes a recursive clause that has no defined endpoint." In other words, you can be targeted under the order even if you're X Degrees of Kevin Bacon away from an insurgent-related financial transaction.)