Unreasonable is not what is being discussed, deliberate calculated bullying and intimidation is. People not appreciating the effect their actions have on others is not what is being suggested, generally, as a reason to knock their wing mirror off, people that feel that being in a more powerful, faster, heavier vehicle who believe they have a greater right to a shared use facility that then use that vehicle to assert their assumed dominance is.
l have followed your link and i think you may be exaggerating a little.
If someone tried to use their vehicle against me as a weapon, losing a wing mirror would be the least of their worries (if I were still standing).
My point was that people can do something (because they can), it can be seen as belligerent, but the reality is it is just fueled by selfish desire, and they don't think any further than that. I'm not even sure that the white Audi altercation was anything more than everyone at that set of lights doing what so many people do in London..race between the lights.
It is really very easy to attain that sort of speed down there if you have a high performance vehicle...they don't call it racecourse 'hill' for nothing.
I've been riding litre class superbikes and 600 class supersports bikes for decades on both the road and track. I've had this one since 09. It weighs 162kg and delivers 110bhp to the back wheel (dyno'd). It could comfortably attain an indicated 130+ going up (not down) that road from the lights.
An M3 wouldn't be a million miles behind its roll on performance from 80mph, and realistically any regular car can hit the 60 NSL from the roundabout to the brow of the hill before that 1/3rd-1/2 mile descent.
M3's are electronically restricted to 155mph....they still have a lot left in reserve when this is removed.