In terms of sportsbetting abusers, the "communication" are carried in form of record on the sportsbook provider's database [again, taking Betby's recent situation out of equation]. The sportsbook provider is the one that made the flag. A flag raised for an offense made by a player on a sportbetting carries on and tied to the person and follow them even when they move casinos.
It might take time for a sportsbook provider to realize that username "holy" on Rollbit is the same person as username "darkness" in, let's say, BetPanda, and UID 12345678 on BC. But eventually algorithm will caught them, and thus, even without offense on Shuffle or BC or BetCoin or DuckDice or other casino who share same provider, the "presumption" [or rather... judgment] will eventually fall to "darkness" and "UID 12345678" in form of either ban-hammer or being limited.
Oh wow! This last two statements speaks a lot of what could be the probable on the series of cases we see here. Especially given the fact that, these game providers do some of these flashings themselves and are responsible for a lot of casinos. It finally explains why, though certain game offerings being accessed by VPN and won, could actually result in the winner being denied withdrawal due to a flag.
Could that be the case for some gamblers really?
Because, at the point of a won bet, it would have just notified the before and focuses be made on the later since, the casino operates within the jurisdiction of the gambler but certain game offerings are accessed using VPN and here, I’m just speculating.