Another thing you may want to do is stop pinging Gmail if it returns a couple of failures. I noticed that when Gmail signed off automatically for any reason, any additional pings caused the account to be locked. This is purely anecdotal so dig into it yourself if you have some time. Last thing you want to do is cause Gmail to block your users' mailboxes.
Thanks for the heads up! Gmail was the first service we implemented and have been testing thoroughly so we had some time to settle on an optimal ping frequency. As for now, we're confident this will not block your Gmail.