How to prevent users from adding content without putting the site into full maintenance mode? We are planning a scheduled update of our site. There is no reason for people to not be able to see the site as anonymous users, or even browse their account if they want to log in.

How can I simply prevent people from adding new content while I do the updates instead of having the site completely down from having to use maintenance mode?
I would uncheck the "add [type] content" permissions checkboxes on the roles that have it, and re-check them after. However, depending on the updates, having people attempting to log in or use other features of your site may be problematic during updates.