I wonder if any warning was given to npm that they would be getting this potentially huge new source of traffic. It doesn't seem to be mentioned anywhere.
This will likely lead to more fault tolerant systems on both projects and hopefully more collaboration & features in the future.
VSCode is used by a non-negligible number of users, and seems to rely on npm to operate at its best. It would have been good etiquette to let npm know, even though they couldn't forecast this exact situation.
However, it isn't bad etiquette and I'm sure Microsoft could get in touch with the devs. Interesting thought.