And what surprises can cost you too much fuel to be safe?
The other day at a major airport in the New York "area", just east of a long line of weather, a jet's crew had declared an emergency due to their fuel quantity. We were parked on the ramp and watched the rescue vehicles go by.
I would guarantee that neither one of the pilots had less than about five or six years working for the company, and the Captain probably three or four times that many years there, if not many more. And many airports are in the area. Think about it-near New York City. Very congested airspace too, especially with weather.
As a contrast, how do we avoid a situation where you are on approach into an airport, even with weather which is reported good, and unforecast fog comes in from a nearby lake or ocean, i.e. Kalispell, MT, by some large mountains? You don't have enough to climb back over to another airport. A foreign pilot's knowledge of MET forecasting might help you in this case? Maybe, but I doubt it.
Maybe we should first call our Dispatcher and tell him to give us fuel for an alternate, because the destination is remote? Many highly-experienced (each with 20 years+, flying transport category and or tactical planes) crews are reluctant to do this when the latest observation forecast looks good. Some of these airports leave on your own-the control tower is closed, with no current braking action reports (in this case, mostly in winter, definitely have reasonable fuel for a suitable alternate with an operating tower and an ILS approach for the forecast winds. Want to gamble on a VOR or NDB approach to save you?).