Originally Posted by LHR/MEL/Europe FF

no.

an example might be this. some low cost carriers prohibit passengers bringing their own food on board the aircraft.

if you decide to bring your own food, because of medical (for example diabetic) or dietary requirements, the crew could ask you not to eat that food, but it would be highly unlikely for that to be a lawful request.

using your analysis, you not eating that food is not breaking any law, however the command itself is not therefore lawful (it is not related to the safety of the aircraft).

the airline may decide it wants to ban you from future travel with them, but there would be no court penalty.

(obviously there might be some exceptions to the above if you eating foods which caused discomfort to other passengers, or breached the laws of the nation on whos carrier you were flying)