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I don't think I've ever met a Dane who would argue that mandatory use of bike lanes is a bad idea. Could you try to explain why you think it's a bad idea? Implemented correctly I see it as a way to make traffic flow smoother and more safe. I'm fully aware that the quality of bike lanes in the UK and other places vary a great deal, but I can't see much wrong with the concept itself.
Benutzungspflicht works great in countries with decent infrastructure. Are you in Switzerland or the UK?