Yeah, that's like setting up a casino in one location with a permanent phone line open to switzerland to ask where the ball landed on the roulette wheels. Doesn't seem like it would hold up under scrutiny.
That's exactly what it was... and it really depends on how a locale defines gambling. In Costa Rica, for instance, you can run the game of chance as long as the money isn't landed onshore, because you're just generating random numbers. IoM was slightly different in that they didn't mind you landing cash, they just wouldn't allow you to generate the numbers. So it seemed natural to co-locate, and then Switzerland was a better backstop than either.
In any case I must admit that the trick, while we agree wouldn't (probably) hold water in court, it might have actually helped (we'll never know) to keep that casino out of some law enforcement watch list... especially if the officers were too overburdened with more important issues / lazy enough / not looking into that kind of activities at the time.