It's utter madness, I agree.
Don't take this as gospel as my memory is rubbish, but I seem to remember that...
In the German case it was the best that anglers could acheive against a powerful 'Green ' (my arse!!) lobby's call for an all out ban on fishing...
Interested angling parties invoked some medieval precedent where every citizen is allowed to harvest rivers and lakes for food in order to avoid a blanket ban. Hence the daft situation where, in law, you must now kill what you catch.
Sounds mad but at least they can still fish, and I bet the majority of serious anglers have deliberately 'faulty' keepnets.
Disclaimer: I have some very weird and involved dreams so this may be, in part or wholly, anecdotal.