Are there any particular policies for dealing with players in OTB tournaments, who have been banned for fair play on one of the top online chess sites?
Do you think there should be? The conditions are totally different, and events with significant money at stake have fair play rules. In any event, I don’t see why the findings of a third party should influence US Chess much.
If an ethics complaint is filed against someone who cheated in online play and the Ethics Committee rules against them, it is entirely possible that the membership of said person will be suspended, in which case they would be unable to play in any USCF-rated event, over the board or otherwise.
The public list of Sanctioned Members includes several who violated the US Chess Code of Ethics in online events. This is documented explicitly for one adult and one minor. Additional minors were suspended for violations during the height of the pandemic, some presumably for online events.
No doubt the Ethics Committee can suspend members for cheating during US Chess online rated events. Some online organizers do make a point to report these violators.
However, I highly doubt cheating in online chess games unrelated to US Chess would result in action by the Ethics Committee. Imagine how many members have cheated over the past three decades - my conservative estimate is 10% of all US Chess members! I know plenty of high profile names who allegedly ran afoul of online Fair Play regulations, but remained US Chess members in good standing. (N.B. Establishing a cheater’s identity may be difficult, even for the chess websites themselves.)
Michael Aigner (ICC Administrator, but not very active since 2019)
Unless the conduct happened in a US Chess rated online event and resulted in a sanction from the Ethics Committee, I don’t care one whit what happens in one’s online play.
The informality of such play carries no reasonable expectation of universal compliance.