We now know that custody of "funds" is not required to be guilty of operating an unlicensed money transmitting business under 18 U.S.C. § 1960 (b)(1)(C).

Accordingly, bitcoin miners, Lightning service providers, and CoinJoin coordinators should perhaps refrain from demonstrating any awareness that their business might touch any funds associated with unlawful activity.

Don't talk about it. Don't write about it. Don't hint at it on t-shirts. Liability now hinges on knowledge and intent, not custody.