The police where I am have a specialist bicycle unit who have ebikes in their stable* so I expect they are aware of the legislation. I've also come across riders of normal bikes who know the correct limits so it's not just an obscure hobby anymore.I live in Denmark and have a throttle on my Tonaro Enduro. The chances on getting stopped on a bike in Denmark are slim.
The chances of getting stopped by a police officer who knows throttles on electric bikes are illegal are even slimmer.
It is ok making laws like this but as an ex police officer I can tell you that there are enough everyday laws without having to remember obscure electric bike laws as well.
Steve
FWIW I think the banning of the independent throttle has much to do with Panasonic who have used leverage to have Euro ebike rules made the same as the Japanese rules, which of course suits their market position beautifully.