Ask HN: user experience - "reasonable" way to logout from Google OpenId ?

My question is about user experience here, and surely someone else has already implemented this, hence my question. I'm currently working on a site for my friends. I've decided to implement account creation and login through only Google OpenId, to get started at least. This all works technically well, and suits the target - my friends all have a GMail account and are willing to avoid creating a new login/pass if possible. One of the drawbacks though is that login out from the site doesn't log you out from Google OpenId (as there's no such thing as single sign out currently in OpenId, if I'm right). As such, if you click on "login" right after clicking on "logout", you'll be in, without any apparent check. So the log-out feature is essentially broken per se. I understand that it's not really the current scope of OpenId etc, but I'd really love to get some feedback from people who may have found work-arounds to still rely on OpenId or Google accounts, more specifically. My current work-around is to display a yellow warning after people log out, stating that they need to logout from gmail, and providing them with a link to do that. What do you think?