I would like some more of those, yes. Tribal bonding is instrumentally useful.
(Of course this is an "all else equal" thing and you want shibboleths that don't turn away outsiders or promote biased thinking or etc etc etc, insert your own caveats. Some of these suggestions seem low-cost and some don't. I'm not persuaded we should adopt any of these in particular, but in principle it seems like a good avenue to explore.)
I'm far from convinced that this approach to rationality should be bound to a single tribal identification. True enough, tribal bonding is useful in the right situations, and identifying strongly with, say, your local meetup group seems like it could be instrumentally valuable for many of our contributors, but it seems far sketchier for LW as a whole: we're delving into difficult and controversial territory here, and going full-bore tribal in our organizational tactics seems like a good way to devalue outside views on our stuff that we really need to be considering.
Is there any rationalist equivalent of "good luck"? I've tried a few variants, such as "work well", "knock them dead", "we're with you" and certain situation-specific phrasings, but haven't found anything that worked generally - though a hearty "may all the gods of Olympus be with you!" can serve. Not a vitally important point, but it would be nice to have something similarly supportive and yet accurate to say.