Earlier quoted context omitted.
The EU could legally jail you the moment you step into its territory, and that includes flights that go through Europe, even without landing.
That doesn’t sound even remotely correct given the nature of the “offense” in this case, for which the remedy is a fine. Can you cite this “jail the moment you step into its territory” thing?
Additionally, while the remedy for this crime is a fine, the remedy for not paying the fine is prison.