Membership plugin: Setting a rule to block widgets which provide loophole to restricted content

Hi there,
I'm building up my website using the 'Membership' plugin to restrict access to non-subscribers. My premium content is made up of articles which are indexed using keywords (categories) and logged-in with dates/time.

I'm finding out that -- though I do manage to 'block' out entirely the content (articles) using the Access Level (negative & positive) rules -- there is still a slight loophole which I'd like to close to shield absolutely the premium content from the view of normal (non-subscribed) 'visitors': the 'Calendar' widget still appears.

I've chosen to have the 'category' and 'calendar' widgets in the margins to enable people to search & retrieve news by date and/or keywords. Whilst all the categories are indeed invisible (ticked in negative rules), the calendar continues to appear for visitors and this means that the days where news is published are highlighted.

A visitor hovering over any of those dates can see the titles of the articles (to which he doesn't have access, but still: those titles provide information which I'd like shielded from non-subscribers). If a visitor clicks on a date however, he gets an error message (which is fine by me) but the fact remains he can gather info just by reading the title of articles...

I hope I've made some sense... To sum it up, my question:

How do I create a (eg. negative) rule in Membership which I can apply so that for instance visitors cannot see 'pages', 'categories', 'posts' etc... but ALSO widgets - and in particular the 'Calendar' widget which provides a loophole of sort to viewing part of the restricted content (specifically the title of posts if one/visitors hover over a specific day)?

Thanks for any help on that one!
Bertrand