Depending on what kind of traffic the router is responding to, it could be about the same to DoS attack a router as a personal system directly connected to a modem. Many routers can be set to ignore specific kinds of traffic, which helps.

Just to be clear I don't believe Torak's story, or anyone else here that claims they got DoS attacked so that they would lose a PK. I wont call it impossible I guess, but personally I don't see anyone taking the time to coordinate this. Here's why in the specific case of Torak:

Torak mentioned he has "proof" of a DoS attack from his router logs. The fact that he has a router indicates that he has a broadband connection, and not dial up. So dude with broadband (attacker) vs. dude with dial up (victim) DoS attack is out (in this case, the broadband connection would easily command enough bandwidth to shut down the dial up user).

Broadband connections typically have far more downstream (download) bandwidth than they do upstream (upload) bandwidth, usually by quite a bit. This means that barring the case of really awesome broadband vs really shitty broadband, there's absolutely no way a single connection could execute a meaningful DoS attack on him even using all of his upload capability for the DoS attack (which would leave no bandwidth for his own CF connection).

It follows from there that any DoS attack against him would have to be executed by multiple conspirators (lets say at least 3, but probably more like half a dozen or better) to have a DoS effect -- and none of the attackers could be the PKer still. These conspirators would all have to be online, know Torak's IP as well as the character he played, have some sort of DoS script prepared in advance, and be ready to launch them when the blood reckoning PKer told them to go.

I guess it's worth noting that IRC could provide his IP address, and Torak's own big mouth would likely provide the character he's playing. If how much I dislike him is any indication, it is probably possible to get half a dozen people that want to piss in his breakfast cereal. Despite all that, though, I think it would still be hard to coordinate something like this on the fly. Not impossible, just very, very unlikely. Given how full of shit Torak is anyway, I'm not willing to give him anywhere close to enough credit to believe the DoS attacked load of crap. I don't think anyone else should either.