I don't think it matters in the 3s or 4s or 5s. I don't think it matters in many places in the 1/2s.
You're not getting paid, so do what you want. Its not a job and you're not a pro, so unless you've vocalized otherwise, there's not an expectation. If you want to help someone out, then do it. If not, don't and don't expect their help later.
That's my genuine feeling on the matter. I very much disagree that it's a "team" sport. Someone may take pride or whatever in being a part of something, but I don't liken it to an actual team event very much at all.