From my outside perspective, it doesn't seem like a mistake on their part at all. Later in the thread you say this accounted for 10% of traffic, mostly 404s. This is (i assume) a hell of a lot of requests, but given npm's position as developer infrastructure, I don't think they could have reasonably expected to melt it. It would have been good of them to give a heads up, but I don't think I'd start assigning blame to the Code team.
From my outside perspective, it doesn't seem like a mistake on their part at all. Later in the thread you say this accounted for 10% of traffic, mostly 404s. This is (i assume) a hell of a lot of requests, but given npm's position as developer infrastructure, I don't think they could have reasonably expected to melt it. It would have been good of them to give a heads up, but I don't think I'd start assigning blame to the Code team.