I don't know about the market manipulation part. But messing with a weather station in an airport, presumably one that is used by pilots and air traffic control for safety critical operations (METAR) is likely to be very illegal, maybe with prison sentences.

I am pretty sure that's the reason why they chose a weather station at an airport. In addition to being public information, it is not something normal people want to mess with.

If you make a mockery of the system and/or dare to thumb your nose at in such a manner they will find a law. The laws are broad for a reason.

>Météo France caught on and filed charges

In Europe, almost certainly yes.

What, fraud? Probably yes