The higher skill a job requires, the less impact quitting without notice should have on colleagues, with respect to "pick up the extra slack." As far as I can tell from reading around, it's going to be a long time after even a two week notice before a replacement is in place (if at all).

You should probably send emails to people about what's where, etc. Or try not to have loose ends. And I can understand colleagues feeling snubbed without a goodbye, much less a happy hour.

I'm not advocating without notice, but when it happens, around "here," I just don't see much of an impact.