> It's the difference of having a group of terrorists[0] in your restaurant everyday audibly planning a terrorist attack versus being the site of a message drop that occurs discreetly.

If we are making a restaurant analogy, I think a more accurate one is that the restaurant provides a sound proof room where a group can enter and discuss anything they want without anybody overhearing. The restaurant does not know what anybody uses that room for. It could be people planning a birthday surprise, it could be a group of terrorists.