I can't speak for the whole world but in Sweden if a bike goes over the speed limit you get a ticket. That's if the cops somehow notice or care.

Sacramento ticketing for speeds over 15mph:

https://www.youtube.com/watch?v=hrdkc7I5o2g

at least once somewhere in the world in the past it was ruled no because you don't have a speedometer

Kinda depend on where you are. In my country the cop rightfully doesn't care, as long as you don't cause problem.

In many places , yes you can be ticketed. Maybe even have your bike impounded like a car.

I dunno why you're getting downvotes, I built my own e bike from a kit, and the speed limiter was enabled via a jumper that was uninstalled by default. Pedal assist was also completely optional. The thing could go 45mph (about 70km/hr) on level ground

I never rode it in pedestrian spaces though, as it would have been very unsafe to do so