But that is what's meant by the isolated example. They make others to whom it has relevance sit up and take notice.But you can only make an example of them when you catch them which right now seems to be only when they kill somebody.
Lots of cases could have the opposite effect, people might just yawn at the commonplace .
100% detection is impossible so we normally deal with the important. If cyclists only kill once year, it hardly ranks as important to the police against all the other road deaths. But when something becomes serious they then act. For example we had a spate of cyclists killed in collisions with trucks about 3 or 4 years ago, so the police acted then. For a couple of months the Met Police blitzed the streets mob handed, stopping thousand of cyclists and drivers at the slightest hint of an infringement. A few were ticketed, most just warned in a friendly fashion and it was even handed, as many cyclists as drivers. It had the desired effect.
If illegal e-bikes start to become a bigger problem, a similar action can be taken. But at present there are far higher priorities and bigger problems for the authorities to deal with, the national spate of youth knife crime for example.
So seizing the odd opportunity to make an example is good enough meanwhile.
.