I personally think of team.tech@ as administrators. I feel responsible for safeguarding the key infrastructure which is mainly Google Apps. I personally as part of my work there hand out accounts to new members; I know Ben has done a lot of Meetup setup and all that dance. I have also negotiated deals with all kinds of parties (Meetup, Slack, a couple of password agents) which I wouldn't consider part of core team.tech@ activities though, and anyone could have done.
That being said, there is no SLA or some such for Team Tech or any other team — we're all volunteers here. Speaking of responsibilities is something very novel inside OTS.
The team's access is of a very sensitive nature: Basically all our services are gated on email, so Google Apps Super Administrator privileges technically grant you control over everything — Twitter, Facebook, Google+, Discourse, Slack, Google Groups, Meetup. That's why I consider the team to have a much higher bar for entry. While everybody can join Team Communications and contribute, that's not so much possible with this kind of privileges.
I don't see any problem with how it currently works but we could strip down team.tech@ a whole lot, rename it to admins@ (or whatever colour we decide to paint that bikeshed) and have a larger team.tech@ which discusses infrastructure. I decreasingly see any value in such teams, though. If it's an open team all discussion should just happen on Discourse and then there's no official way to become part of the team other than actually doing stuff.