Two comments: the gmail outage screwed things up in subtle ways besides the gio bouncing issue. I use the gmail client but most of my email goes through non-gmail services. During the outage, the gmail client began failing to poll my non-gmail addresses. The effect was that gio appeared to have quit sending me email, although it was working fine. I was scratching my head because my gio email delivery log looked fine, but I wasn't receiving messages. After poking around, I discovered the problem and went to gmail settings to manually force gmail to read my non-gmail addresses. If members of your group are having issues, this could be one source.
I am rethinking my choice of email clients. I started using the gmail client to become familiar with it because I found myself helping a lot of people with gmail issues. Maybe it is time go back to Outlook or Thunderbird. Or something else.
Second comment: Google appears to be entering rough regulatory waters and I would not be surprised if their business model changes in the next few years, but I doubt that this outage is related. Reports say that an internal automatic storage allocation system failed and some of their systems ran out of space for 40 minutes or so. Yikes! That's the kind of scenario that nightmares are made from. At Google's scale, that could cause a lot of damage, some of which might be subtle and cause instability that lasts longer than you would expect. Therefore, I would keep an eye on Google services for a while.
Best, Marv
Marvin Waschke