Weight vs Mass
"weigh more than 250g". Sloppy terminology. For measuring onions in a market with a balance then you can get away with calling mass weight (although physicists cringe) but for a drone that flies up and down and could be anywhere in the world then there is no universal way to convert mass (g) to weight (N).
Is there a standard acceleration to convert mass to weight? If so what happens if you live somewhere at one of the extremes where this varies? Can you buy gold at the equator (low g) and sell it at high latitude (high g) ? Mass is the same but weight will be different. This gives me a idea...!
There are industries where you can get away with this kind of sloppiness but aviation is not one of them.