You just proved my point with those links. I was going to say, somebody will get him bad for this kind of "prank."
To me, a prank has to be funny, that's the whole point. This was utterly cringeworthy. Sure, everybody has different tolerance level; some people might find it funny when somebody comes and kicks him hard in the back. People laugh, there are plenty of videos of people being harassed and others enjoying on their behalf. What's disgusting to me is that the victims sometimes go through severe trauma so that the perpetrator gets some laugh or makes some money out of it. Your definition of prank is different to mine; I just didn't find it funny at all. It was more of a scare tactic than a prank.

As for the last video, do some searches on this guy and his past videos. You will understand what I meant.