Banning via console does exactly that. It bans. And a ban prevents someone from joining a server. It does nothing if they are already on the server. SourceMod bans (sm_ban) kicks as well. So you could in theory, console ban an entire server and none of them would ever know until they left and tried to return. One could, speaking purely hypothetically here, write a script that would ban the whole server every 15 minutes. Might take a couple of days but eventually the server would empty out (because all the regulars would be banned) and then we could replace it with a much better map, like 2Fort for example. Not that I would ever do such a thing. So you kicking the players after jhnsn console banned them was necessary to get them off the server. Jhnsn could have kicked them via console after he banned, but like most advisors, he's lazy.
Not really. Yesterday I got 2 mutes, a ban, and a domination on Main. That's an Idol hat trick