Quote:
In the movie, there's an actual scene where we see Arthur and Ford's first meeting, as a flashback. And Ford's explanation of that moment is (now that I think back on it) the reason he chose the name "Ford Prefect". It's all so clear now.

I agree this made much more sense, but it made me realise that when Zaphod and Ford meet on the spaceship, Zaphod should not know him as Ford. Since Zaphod didn't know he was there and the name Ford Prefect was one he chose specificly to blend in on Earth.