But that will only be the case with sites which have a fault in them and the person is exploiting that flaw. The method on its own wouldn't be +EV , and since substrata already mentioned that it doesn't involve taking advantage of a flaw, we can rule that out.
Right, and he also said it doesn't involve a jackpot. Sometimes jackpots can be +EV for the player - maybe it's being paid out of the site's pocket as a promotion, or maybe it's a progressive pot that fills over time from other players making losing bets.
But if there's no flaw and no jackpot then I don't see where the +EV is going to come from.