Happens all the time the world over, cars regularly mount the pavement to pass other traffic, or just to take a sneaking shortcut - search on youtube if you have been lucky enough to miss this yourself.
I personally count a car driving any distance on a pavement something I don't want to see.
If you claim never to have seen that happen, then you must live in a hugely law abiding place. I live in a small town with a pretty old average age, and I see this regularly here. In London it was worse. Maybe as a cyclist you look out for these things more, or maybe you just get to see them more due to your positioning.
First search result: https://www.youtube.com/watch?v=Iuhblb_9qec