These videos popped up yesterday. I don’t know if these guys are related to the government. Something similar happened a couple of years ago in north Seoul. It could also be gangsters punishing these vendors for not playing by their rules.
You can see the police don’t feel like doing anything about it.
https://www.youtube.com/watch?v=Fj4IPtsiuWY
And as of November 19th 2014 seems to have happened again..