To simply hide the toolbar would be a solution, but It would be nice to have the chance to deactivate globally all the plugin’s features for certain page/posts, to avoid incompatibility with other plugins or custom css.
Thanks for any help.
So, I was looking into doing this, but I actually don’t think it’s necessary to make any changes. I’d forgotten about the pre_option filter:
http://codex.wordpress.org/Plugin_API/Filter_Reference/pre_option_%28option_name%29
WordPress already includes the ability to filter any option, so that you can dynamically alter it for a given page view.