I've recently changed my site access to exclude Guests - [Allow Guest access] is unchecked and [Hide Panels] is checked.  My problem is that the home page continues to say there are guests online.  The number never goes below 2 guests, but sometimes says as high as 4.

1. My main concern is that there are 2 people who have been connected to the site since before I disabled guest access and are still able to visit our pages at will.  Is this a possibility?

2. Is there a way to force-disconnect all visitors and members from the site.  The maintenance mode description seems to indicate that it just disables any new logins.  Is this true?

You may also want to bare in mind that Guests that your seeing online will be the bots from search engines crawling your website for content.

well no. With guest access being denied you will still see that there are guests online because you are a guest until you login. So bots will still try to trawl but they will only hit the login page (and homepage if its not set to a private website).