Yes, it's the same when you resign from a group, at least with regards to completing team matches and votechess alerts.
That receiving group alerts and messages does not happen in my experience though.
As for the votechess alerts I just ignore them:)
I was kicked out from a group, and I wasn't given time to untrack the comment box, in several vote chess games I was playing for the team. We had a 7 day pr. move game going, so I figure it probably will go on, for another year or two.
I'm also alerted of group activity, and I've been receiving a lot of the group mails. On the group homepage I no longer have a Group Menu, and no way to change the group alerts. I've contacted the group admin, who decline to remove me from their list, so I figure this will go on for as long as I'm a member of Chess.com.
There must be a problem controlling what goes on in all the different groups, and I have no problem with Super Admins having great freedom to run their groups as they chose, here at Chess.com. But I believe that serving your paying members should be your first priority, and that we should be provided with a reliable retreat, from the varying regimes the different SAs impose on their members.