The other way to prove its existance is to try riding a big*, modern motorbike after only ever riding pushbikes. Ride it like a pushbike and however quick you are on a pushbike, getting them to go round corners is impossible if you treat them in the same way, took me at least a week to get the body language dialled for getting my scooter to turn in properly, then steping upto motorbikes – same again, big bikes – same again, unlike a push bike it wont turn in with a shift in your weight, it’ll only do it if you countersteer to get the weight of it over, and the same is true for the exit, you have to turn sharper to straighten up.
*I mean bikes where the engine is relatively high and your crouched over it, Bonneville/Bullet/Comando/HD style bikes seem different again as the COG is lower.